Use bool for solib::symbols_loaded

This changes solib::symbols_loaded to be of type 'bool'.

Approved-By: Simon Marchi <simon.marchi@efficios.com>

gdb/solib.c

diff --git a/gdb/solib.c b/gdb/solib.c
index dfcee43..fdefdf0 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -593,7 +593,7 @@ solib::clear ()
   this->abfd = nullptr;
 
   /* Our caller closed the objfile, possibly via objfile_purge_solibs.  */
-  this->symbols_loaded = 0;
+  this->symbols_loaded = false;
   this->objfile = nullptr;
 
   this->addr_low = this->addr_high = 0;
@@ -653,7 +653,7 @@ solib_read_symbols (solib &so, symfile_add_flags flags)
 	      so.objfile->addr_low = so.addr_low;
 	    }
 
-	  so.symbols_loaded = 1;
+	  so.symbols_loaded = true;
 	}
       catch (const gdb_exception_error &e)
 	{
@@ -1259,7 +1259,7 @@ reload_shared_libraries_1 (int from_tty)
   for (solib &so : current_program_space->solibs ())
     {
       const char *found_pathname = NULL;
-      bool was_loaded = so.symbols_loaded != 0;
+      bool was_loaded = so.symbols_loaded;
       symfile_add_flags add_flags = SYMFILE_DEFER_BP_RESET;
 
       if (from_tty)

gdb/solist.h

diff --git a/gdb/solist.h b/gdb/solist.h
index 336bb01..8ad0aef 100644
--- a/gdb/solist.h
+++ b/gdb/solist.h
@@ -77,7 +77,9 @@ struct solib : intrusive_list_node<solib>
      current_sos must initialize these fields to 0.  */
 
   gdb_bfd_ref_ptr abfd;
-  char symbols_loaded = 0;	/* flag: symbols read in yet?  */
+
+  /* True if symbols have been read in.  */
+  bool symbols_loaded = false;
 
   /* objfile with symbols for a loaded library.  Target memory is read from
      ABFD.  OBJFILE may be NULL either before symbols have been loaded, if