[This file contains two alternative recipes for compiling X11 with GCC.
The first alternative puts libgcc.a into the shared X library; the second
does not.  Neither alternative works on all kinds of systems.
It may be that when using GCC 2.4, both alternatives work okay on 
relatively recent Sparc systems.  The first alternative is likely
not to work on a Sun 3 without hardware floating point.]

How to compile X11R5 (patch level 11) with GCC version 2:

The patches include support for building the shared libraries with GCC
2 on the Sparc and 68k machines.  This version includes the necessary
parts of libgcc.a in the shared library for X, in case functions in
that library need it.  Thus the default behavior is now to build
everything, including the libraries, with gcc.

If you build the shared library this way, it may not work with 
executables made with older versions of GCC (2.3.3 and earlier).
If that happens, relink those executables with the latest GCC.
IF YOU THINK YOU MIGHT COMPILE X FOR SOLARIS 2, then you really don't
need this patch: get /contrib/R5.SunOS5.patch.tar.Z from
export.lcs.mit.edu instead.  It has everything you need to do the
build for Solaris 2, sets you up to everything with GCC, and is
backward compatible with Sunos 4.*.  Get the the README
(/contrib/R5.SunOS5.patch.README at export) for more info.

If you see undefined symbols _dlopen, _dlsym, or _dlclose when linking
with -lX11, compile and link against the file mit/util/misc/dlsym.c in
the MIT X11R5 distribution.  Alternatively, do dynamic linking
by using a non-GNU ld.

mit/config/Imake.tmpl -- Do not set -fstrength-reduce if we have GCC 2.
If -fstrength-reduce (or any other -f option) is a major win, then it
will most likely be turned on by -O2 optimization.

mit/config/sunLib.rules -- If HasGcc and GccVersion > 1 are true, then
use gcc -fpic to generate PIC code.  Make sure that gcc does not use
gas (the GNU assembler) when compiling PIC code; gas does not assemble
it correctly.

***If you have gas installed where gcc uses it by default, you might have
to add -B/bin/ to the PositionIndependentCFlags.***

mit/config/site.def -- Define GccVersion to be 2.

mit/config/sun.cf -- When compiling with GCC 2, use -O2 optimization.

mit/config/sunLib.rules -- When compiling with GCC 2, use -fpic for
position independent code generation.

mit/rgb/Imakefile -- No longer need to compile some modules with 
cc on the Sparc since GCC 2 produces proper -fpcc-struct-return code.

mit/server/os/Imakefile -- Likewise.

mit/server/ddx/sun/Imakefile -- When compiling with GCC 2, some modules
should be compiled with -fvolatile.

mit/clients/twm/Imakefile -- Fix bad decls of malloc, realloc in gram.c.

mit/lib/X/Imakefile -- Make libgcc.a a required lib for libX11.so

*** mit/clients/twm/Imakefile	Mon May 17 22:05:22 1993
--- new/clients/twm/Imakefile	Mon May 17 22:28:46 1993
***************
*** 32,41 ****
--- 32,48 ----
  ComplexProgramTarget(twm)
  InstallNonExecFile(system.twmrc,$(TWMDIR))
  
+ #if HasGcc && GccVersion > 1 && defined (SunArchitecture)
  gram.h gram.c: gram.y
  	yacc $(YFLAGS) gram.y
+ 	sed -e 's/^extern char \*malloc(), \*realloc();//g' y.tab.c >gram.c
+ 	$(MV) y.tab.h gram.h
+ #else
+ gram.h gram.c: gram.y
+ 	yacc $(YFLAGS) gram.y
  	$(MV) y.tab.c gram.c
  	$(MV) y.tab.h gram.h
+ #endif
  
  clean::
  	$(RM) y.tab.h y.tab.c lex.yy.c gram.h gram.c lex.c deftwmrc.c 
*** mit/config/Imake.tmpl	Mon May 17 22:02:57 1993
--- new/config/Imake.tmpl	Mon May 17 22:15:06 1993
***************
*** 500,506 ****
--- 500,510 ----
  #endif
  #ifndef CcCmd
  #if HasGcc
+ #if GccVersion > 1
+ #define CcCmd gcc -fpcc-struct-return
+ #else
  #define CcCmd gcc -fstrength-reduce -fpcc-struct-return 
+ #endif
  #else
  #define CcCmd cc
  #endif
*** mit/config/site.def	Mon May 17 22:02:44 1993
--- new/config/site.def	Mon May 17 22:22:28 1993
***************
*** 25,31 ****
  
  #ifdef BeforeVendorCF
  
! /* #define HasGcc YES */
  
  #endif /* BeforeVendorCF */
  
--- 25,33 ----
  
  #ifdef BeforeVendorCF
  
! #define HasGcc YES
! /* GccVersion > 1 implies building shared libraries with gcc */
! #define GccVersion 2
  
  #endif /* BeforeVendorCF */
  
*** mit/config/sun.cf	Mon May 17 22:03:02 1993
--- new/config/sun.cf	Mon May 17 22:24:55 1993
***************
*** 41,49 ****
--- 41,55 ----
  
  #if HasGcc
  
+ #if GccVersion > 1
+ #define OptimizedCDebugFlags -O2
+ #else
+ #define OptimizedCDebugFlags -O
  #define SharedLibraryCcCmd cc
  #define ExtraLoadFlags -B/usr/bin/
  #define AllocateLocalDefines /**/
+ #endif
+ 
  
  .c.o:
  	$(CC) -c $(CFLAGS) $*.c
*** mit/config/sunLib.rules	Mon May 17 22:02:46 1993
--- new/config/sunLib.rules	Mon May 17 22:19:06 1993
***************
*** 23,29 ****
--- 23,33 ----
  #define SharedLibraryLoadFlags -assert pure-text
  #endif
  #ifndef PositionIndependentCFlags
+ #if defined(HasGcc) && GccVersion > 1
+ #define PositionIndependentCFlags -fpic
+ #else
  #define PositionIndependentCFlags -pic
+ #endif
  #endif
  
  /*
*** mit/lib/X/Imakefile	Mon May 17 22:05:03 1993
--- new/lib/X/Imakefile	Mon May 17 22:32:26 1993
***************
*** 9,14 ****
--- 9,31 ----
  #define MotifBC NO
  #endif
  
+ #if defined(SunArchitecture)
+ #if SystemV4
+ #if HasGcc
+ REQUIREDLIBS= -lgcc -lc
+ #else
+ REQUIREDLIBS= -lc
+ #endif
+ #else
+ #if HasGcc && GccVersion > 1
+ XCOMM Hack to fix gcc 2 ``-nostdlib'' deficiency on SunOS 4.x
+ REQUIREDLIBS= `gcc -v 2>&1 | awk '{print $$4}' | sed -e 's/specs$$/libgcc.a/'`
+ #else
+ REQUIREDLIBS=
+ #endif
+ #endif
+ #endif
+ 
  #ifndef BuildXimp
  #define BuildXimp NO
  #endif
*** mit/rgb/Imakefile	Mon May 17 22:05:31 1993
--- new/rgb/Imakefile	Mon May 17 22:25:30 1993
***************
*** 17,23 ****
  #if !(defined(SGIArchitecture) || SystemV4)
         DBMLIB = -ldbm
  #endif
! #if defined(SparcArchitecture) && HasGcc
             CC = cc
      CCOPTIONS = /**/
      EXTRA_LOAD_FLAGS = /**/
--- 17,23 ----
  #if !(defined(SGIArchitecture) || SystemV4)
         DBMLIB = -ldbm
  #endif
! #if defined(SparcArchitecture) && HasGcc && GccVersion <= 1
             CC = cc
      CCOPTIONS = /**/
      EXTRA_LOAD_FLAGS = /**/
*** mit/server/ddx/sun/Imakefile	Mon May 17 22:05:57 1993
--- new/server/ddx/sun/Imakefile	Mon May 17 22:27:23 1993
***************
*** 43,48 ****
--- 43,53 ----
  LinkFile(sunGX.o,sunGX.o.dist)
  #endif
  
+ #if HasGcc && GccVersion > 1
+ SpecialObjectRule(sunCG2C.o,sunCG2C.c,-fvolatile)
+ SpecialObjectRule(sunCG2M.o,sunCG2M.c,-fvolatile)
+ #endif
+ 
  sunInitExtMono.o: $(ICONFIGFILES)
  ObjectFromSpecialSource(sunInitExtMono,../mi/miinitext,-UPEXEXT)
  ObjectFromSpecialSource(sunInitMono,sunInit,-DMONO_ONLY)
*** mit/server/os/Imakefile	Mon May 17 22:05:46 1993
--- new/server/os/Imakefile	Mon May 17 22:26:02 1993
***************
*** 132,138 ****
  SpecialObjectRule(osinit.o,$(ICONFIGFILES),$(ADM_DEFINES))
  SpecialObjectRule(WaitFor.o,$(ICONFIGFILES),$(EXT_DEFINES))
  SpecialObjectRule(fonttype.o,$(ICONFIGFILES),$(FONT_DEFINES))
! #if defined(SparcArchitecture) && HasGcc
  oscolor.o: $(ICONFIGFILES)
  	$(RM) $@
  	cc -c $(DBM_DEFINES) $(CDEBUGFLAGS) $(ALLDEFINES) $*.c
--- 132,138 ----
  SpecialObjectRule(osinit.o,$(ICONFIGFILES),$(ADM_DEFINES))
  SpecialObjectRule(WaitFor.o,$(ICONFIGFILES),$(EXT_DEFINES))
  SpecialObjectRule(fonttype.o,$(ICONFIGFILES),$(FONT_DEFINES))
! #if defined(SparcArchitecture) && HasGcc && GccVersion <= 1
  oscolor.o: $(ICONFIGFILES)
  	$(RM) $@
  	cc -c $(DBM_DEFINES) $(CDEBUGFLAGS) $(ALLDEFINES) $*.c


[This is the older version]

How to compile X11R5 (patch level 11) with GCC version 2:

The patches include support for building the shared libraries with GCC 2 on 
the Sparc and 68k machines.

NOTE: Such shared libraries built with GCC version 2.3 DID NOT WORK
with executables previously linked using Sun CC!  This is because
neither those executables nor the gcc-compiled shared libraries contain
libgcc.a.  The shared libraries did work with executables linked using
GCC (running the Sun linker, of course) because GCC tells the linker to
link in libgcc.a.  Because of these limitations the default behavior is
to NOT build the shared libraries with gcc.

Changes in GCC 2.4 seem to have eliminated the problem, and such a
shared library now seems work with all executables.  If you want the
gcc-compiled shared libraries turn on "Gcc2BuildLibs" in site.def.  If
you try this, please tell bug-gcc@prep.ai.mit.edu whether it works.

Sun forgot to include a static version of libdl.a with some versions
of SunOS (4.1 mainly).  If you see undefined symbols _dlopen, _dlsym,
or _dlclose when linking with -lX11, compile and link against the file
mit/util/misc/dlsym.c in the MIT X11R5 distribution.

mit/config/Imake.tmpl -- Do not set -fstrength-reduce if we have GCC 2.  If
-fstrength-reduce (or any other -f option) is a major win, then it will
most likely be turned on by -O2 optimization.

mit/config/sunLib.rules -- If HasGcc2 and Gcc2BuildLibs are defined, then 
use gcc -fpic to generate PIC code.  Make sure that gcc does not use gas (the 
GNU assembler) when compiling PIC code; gas does not assemble it correctly.  
If you have gas installed where gcc uses it by default, you might have to add
-B/bin/ to the PositionIndependentCFlags.

mit/config/site.def -- Define HasGcc2 to be YES.

mit/config/sun.cf -- When compiling with GCC 2, use -O2 optimization.

mit/rgb/Imakefile -- No longer need to compile some modules with 
cc on the Sparc since GCC 2 produces proper -fpcc-struct-return code.

mit/server/os/Imakefile -- Likewise.

mit/clients/twm/Imakefile -- fix bad decls of malloc, realloc in gram.c.

*** mit/config/Imake.tmpl.ORIG	Tue Dec 31 11:07:56 1991
--- mit/config/Imake.tmpl	Tue Dec 31 12:30:47 1991
***************
*** 499,508 ****
--- 499,512 ----
  #define HasGcc NO
  #endif
  #ifndef CcCmd
+ #if HasGcc2
+ #define CcCmd gcc -fpcc-struct-return
+ #else
  #if HasGcc
  #define CcCmd gcc -fstrength-reduce -fpcc-struct-return 
  #else
  #define CcCmd cc
+ #endif
  #endif
  #endif
  #if HasFortran
*** mit/config/sunLib.rules.ORIG	Tue Dec 31 11:11:24 1991
--- mit/config/sunLib.rules	Tue May  5 12:26:12 1992
***************
*** 23,30 ****
--- 23,34 ----
  #define SharedLibraryLoadFlags -assert pure-text
  #endif
  #ifndef PositionIndependentCFlags
+ #if defined(HasGcc2) && defined (Gcc2BuildLibs)
+ #define PositionIndependentCFlags -fpic
+ #else
  #define PositionIndependentCFlags -pic
  #endif
+ #endif
  
  /*
   * InstallSharedLibrary - generate rules to install the shared library.
*** mit/config/site.def.ORIG	Tue Dec 31 11:13:49 1991
--- mit/config/site.def	Tue Dec 31 12:02:59 1991
***************
*** 25,31 ****
  
  #ifdef BeforeVendorCF
  
! /* #define HasGcc YES */
  
  #endif /* BeforeVendorCF */
  
--- 25,33 ----
  
  #ifdef BeforeVendorCF
  
! #define HasGcc YES 
! #define HasGcc2 YES
! /* #define Gcc2BuildLibs YES */
  
  #endif /* BeforeVendorCF */
  
*** mit/config/sun.cf.ORIG	Tue Dec 31 11:13:57 1991
--- mit/config/sun.cf	Tue May  5 12:29:50 1992
***************
*** 34,42 ****
--- 41,61 ----
  
  #if HasGcc
  
+ #if defined(HasGcc2) 
+ #define OptimizedCDebugFlags -O2 
+ /* Leave Alone XXX */
+ #else 
+ #define OptimizedCDebugFlags -O
  #define SharedLibraryCcCmd cc
  #define ExtraLoadFlags -B/usr/bin/
  #define AllocateLocalDefines /**/
+ #endif
+ 
+ #if !defined(Gcc2BuildLibs)
+ #define SharedLibraryCcCmd cc
+ #define ExtraLoadFlags -B/usr/bin/
+ #define AllocateLocalDefines /**/
+ #endif
  
  .c.o:
  	$(CC) -c $(CFLAGS) $*.c
*** mit/rgb/Imakefile.ORIG	Wed Jan 15 16:43:18 1992
--- mit/rgb/Imakefile	Thu Jan  2 13:34:09 1992
***************
*** 17,23 ****
  #if !(defined(SGIArchitecture) || SystemV4)
         DBMLIB = -ldbm
  #endif
! #if defined(SparcArchitecture) && HasGcc
             CC = cc
      CCOPTIONS = /**/
      EXTRA_LOAD_FLAGS = /**/
--- 17,23 ----
  #if !(defined(SGIArchitecture) || SystemV4)
         DBMLIB = -ldbm
  #endif
! #if defined(SparcArchitecture) && HasGcc && !defined(HasGcc2)
             CC = cc
      CCOPTIONS = /**/
      EXTRA_LOAD_FLAGS = /**/
*** mit/server/os/Imakefile.ORIG	Wed Jan 15 16:46:23 1992
--- mit/server/os/Imakefile	Wed Jan 15 16:46:48 1992
***************
*** 132,138 ****
  SpecialObjectRule(osinit.o,$(ICONFIGFILES),$(ADM_DEFINES))
  SpecialObjectRule(WaitFor.o,$(ICONFIGFILES),$(EXT_DEFINES))
  SpecialObjectRule(fonttype.o,$(ICONFIGFILES),$(FONT_DEFINES))
! #if defined(SparcArchitecture) && HasGcc
  oscolor.o: $(ICONFIGFILES)
  	$(RM) $@
  	cc -c $(DBM_DEFINES) $(CDEBUGFLAGS) $(ALLDEFINES) $*.c
--- 132,138 ----
  SpecialObjectRule(osinit.o,$(ICONFIGFILES),$(ADM_DEFINES))
  SpecialObjectRule(WaitFor.o,$(ICONFIGFILES),$(EXT_DEFINES))
  SpecialObjectRule(fonttype.o,$(ICONFIGFILES),$(FONT_DEFINES))
! #if defined(SparcArchitecture) && HasGcc && !defined(HasGcc2)
  oscolor.o: $(ICONFIGFILES)
  	$(RM) $@
  	cc -c $(DBM_DEFINES) $(CDEBUGFLAGS) $(ALLDEFINES) $*.c
*** 1.1 1992/09/08 19:52:07
--- mit/server/ddx/sun/Imakefile        1992/09/08 21:10:22
***************
*** 43,48 ****
--- 43,53 ----
  LinkFile(sunGX.o,sunGX.o.dist)
  #endif

+ #if HasGcc2
+ SpecialObjectRule(sunCG2C.o,sunCG2C.c,-fvolatile)
+ SpecialObjectRule(sunCG2M.o,sunCG2M.c,-fvolatile)
+ #endif
+ 
  sunInitExtMono.o: $(ICONFIGFILES)
  ObjectFromSpecialSource(sunInitExtMono,../mi/miinitext,-UPEXEXT)
  ObjectFromSpecialSource(sunInitMono,sunInit,-DMONO_ONLY)

*** /tmp/RCSAa24446     Tue Sep 15 12:23:32 1992
--- mit/clients/twm/Imakefile   Thu Aug 13 18:18:07 1992
***************
*** 32,41 ****
--- 32,48 ----
  ComplexProgramTarget(twm)
  InstallNonExecFile(system.twmrc,$(TWMDIR))
  
+ #if HasGcc2 && defined (SunArchitecture)
  gram.h gram.c: gram.y
        yacc $(YFLAGS) gram.y
+       sed -e 's/^extern char \*malloc(), \*realloc();//g' y.tab.c >gram.c
+       $(MV) y.tab.h gram.h
+ #else
+ gram.h gram.c: gram.y
+       yacc $(YFLAGS) gram.y
        $(MV) y.tab.c gram.c
        $(MV) y.tab.h gram.h
+ #endif
  
  clean::
        $(RM) y.tab.h y.tab.c lex.yy.c gram.h gram.c lex.c deftwmrc.c