Bug 702115: use the offical method to detect gcc

In the early days of autoconf there was no defined way to check if the selected
compiler was gcc (or compatible) or not. Projects used the autoconf internal
shell variable ac_cv_prog_gcc to get that info.

autoconf introduced the GCC shell variable as the official way to know (a long
time ago), and we never revised our configure.ac to reflect that.

This does so.

1 files changed, 19 insertions, 19 deletions

diff --git a/configure.ac b/configure.ac
index 167d4905d..cc82587f7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -284,26 +284,26 @@ CFLAGS_LARGEFILE=""
 
 case $host in
         *-linux*|*-gnu)
-        if test $ac_cv_prog_gcc = yes; then
+        if test $GCC = yes; then
             CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
             CC_DBG_FLAGS_TO_TRY="-gdwarf-2 -g3 -O0"
         fi
         ;;
         *bsd*)
-        if test $ac_cv_prog_gcc = yes; then
+        if test $GCC = yes; then
             CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
             CC_DBG_FLAGS_TO_TRY="-gdwarf-2 -g3 -O0"
         fi
         ;;
         *-darwin*)
-        if test $ac_cv_prog_gcc = yes; then
+        if test $GCC = yes; then
             CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
             CC_DBG_FLAGS_TO_TRY="-gdwarf-2 -g3 -O0"
         fi
         SET_DT_SONAME=""
         ;;
         *-mingw*|*-msys*|*-cygwin*)
-        if test $ac_cv_prog_gcc = yes; then
+        if test $GCC = yes; then
             CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
             CC_DBG_FLAGS_TO_TRY="-gdwarf-2 -g3 -O0"
         fi
@@ -313,10 +313,10 @@ case $host in
         CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
         CFLAGS_LARGEFILE="-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64"
         # the trailing space is required!
-        if test $ac_cv_prog_gcc = no; then
+        if test $GCC = no; then
             SET_DT_SONAME="-h "
         fi
-        if test $ac_cv_prog_gcc = yes; then
+        if test $GCC = yes; then
             CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
             CC_DBG_FLAGS_TO_TRY="-gdwarf-2 -g3 -O0"
         else
@@ -324,7 +324,7 @@ case $host in
         fi
         ;;
         *-aix*)
-        if test $ac_cv_prog_gcc = yes; then
+        if test $GCC = yes; then
             CC_OPT_FLAGS_TO_TRY="-O2 -DNDEBUG"
             CC_DBG_FLAGS_TO_TRY="-gdwarf-2 -g3 -O0"
             SET_DT_SONAME="so"
@@ -335,7 +335,7 @@ esac
 AC_SUBST(SET_DT_SONAME)
 
 
-if test $ac_cv_prog_gcc = yes; then
+if test $GCC = yes; then
     cflags_to_try="-Wall -Wstrict-prototypes -Wundef \
 -Wmissing-declarations -Wmissing-prototypes -Wwrite-strings \
 -fno-strict-aliasing -Werror=declaration-after-statement \
@@ -1197,7 +1197,7 @@ else
         SHARE_ZLIB=0
         ZLIBDIR=$srcdir/zlib
 
-        if test x"$ac_cv_prog_gcc" = x"yes"; then
+        if test x"$GCC" = x"yes"; then
           ZLIBCFLAGS="-Wno-write-strings"
         fi
   else
@@ -1443,7 +1443,7 @@ if test x"$SHARE_LIBTIFF" = x"0" ; then
       fi
       cd "$olddir"
 
-      if test x"$ac_cv_prog_gcc" = x"yes"; then
+      if test x"$GCC" = x"yes"; then
         TIFFCFLAGS="-Wno-write-strings $CFLAGS_NMI $CFLAGS_NUD -DJPEG_LIB_MK1_OR_12BIT=0"
       fi
       # if we're building with our own libjpeg, or we have another libjpeg available, allow jpeg compression in TIFF
@@ -1735,7 +1735,7 @@ if test x$with_luratech != xno; then
           JBIG2_AUTOCONF_CFLAGS="-DUSE_LDF_JB2 -DMAC -DMAC_OS_X_BUILD -fsigned-char"
         ;;
         *-aix*)
-          if test $ac_cv_prog_gcc = yes; then
+          if test $GCC = yes; then
             JBIG2_AUTOCONF_CFLAGS="-DUSE_LDF_JB2 -fsigned-char -DLINUX=1 -DFORTE"
           else
             JBIG2_AUTOCONF_CFLAGS="-DUSE_LDF_JB2 -qchars=signed -DLINUX=1 -DFORTE"
@@ -1876,7 +1876,7 @@ if test x$with_luratech != xno; then
           JPX_AUTOCONF_CFLAGS="-DUSE_LWF_JP2 -DMAC -DMAC_OS_X_BUILD"
         ;;
         *-aix*)
-          if test $ac_cv_prog_gcc = yes; then
+          if test $GCC = yes; then
             JPX_AUTOCONF_CFLAGS="-DUSE_LWF_JP2 -fsigned-char -DLINUX=1 -DFORTE"
           else
             JPX_AUTOCONF_CFLAGS="-DUSE_LWF_JP2 -qchars=signed -DLINUX=1 -DFORTE"
@@ -1917,7 +1917,7 @@ AC_CHECK_FUNCS([fseeko], [CFLAGS_OPJ_HAVE_FSEEKO="-DOPJ_HAVE_FSEEKO=1"], [CFLAGS
 JPX_SSE_CFLAGS=""
 
 if test "x$HAVE_SSE2" = "x" ; then
-  if test $ac_cv_prog_gcc = yes; then
+  if test $GCC = yes; then
     JPX_SSE_CFLAGS="-U__SSE__"
   fi
 fi
@@ -2721,7 +2721,7 @@ AC_ARG_ENABLE([hidden-visibility],
         [hide all shared library symbols which are not part of its public API]),
     [hide_symbols=yes])
 
-if test x$hide_symbols = xyes -a $ac_cv_prog_gcc = yes; then
+if test x$hide_symbols = xyes -a $GCC = yes; then
     attr_default="__attribute__((visibility(\\\"default\\\")))"
     attr_hidden="__attribute__((visibility(\\\"hidden\\\")))"
 fi
@@ -2733,7 +2733,7 @@ case $host in
       PCL_DYNAMIC_LDFLAGS="-shared -Wl,\$(LD_SET_DT_SONAME)\$(LDFLAGS_SO_PREFIX)\$(PCL_SONAME_MAJOR)"
       XPS_DYNAMIC_LDFLAGS="-shared -Wl,\$(LD_SET_DT_SONAME)\$(LDFLAGS_SO_PREFIX)\$(XPS_SONAME_MAJOR)"
       PDL_DYNAMIC_LDFLAGS="-shared -Wl,\$(LD_SET_DT_SONAME)\$(LDFLAGS_SO_PREFIX)\$(GPDL_SONAME_MAJOR)"
-      if test $ac_cv_prog_gcc = yes; then
+      if test $GCC = yes; then
         # GCC high level flag
         DYNAMIC_LIBS="-rdynamic"
       else
@@ -2788,7 +2788,7 @@ case $host in
       SO_LIB_EXT=".dylib"
     ;;
     *-sun*|*-solaris*)
-      if test $ac_cv_prog_gcc = yes; then
+      if test $GCC = yes; then
         DYNAMIC_CFLAGS="-fPIC $DYNAMIC_CFLAGS"
       else
         DYNAMIC_CFLAGS="-KPIC $DYNAMIC_CFLAGS"
@@ -2807,7 +2807,7 @@ case $host in
       SO_LIB_EXT=".so"
     ;;
     *-aix*)
-      if test $ac_cv_prog_gcc = yes; then
+      if test $GCC = yes; then
         DYNAMIC_CFLAGS="-fPIC $DYNAMIC_CFLAGS"
         GCFLAGS="-Wl,-brtl -D_LARGE_FILES $GCFLAGS"
         GS_DYNAMIC_LDFLAGS="-shared -Wl,-brtl,-G -fPIC"
@@ -2826,7 +2826,7 @@ case $host in
 esac
 
 if test x$hide_symbols = xyes ; then
-  if test $ac_cv_prog_gcc = yes; then
+  if test $GCC = yes; then
     DYNAMIC_CFLAGS="$DYNAMIC_CFLAGS -fvisibility=hidden"
   fi
   DYNAMIC_CFLAGS="$DYNAMIC_CFLAGS -DGSDLLEXPORT=\"$attr_default\""
@@ -3274,7 +3274,7 @@ AC_SUBST(VERSIONED_PATH)
 # NOTE: Strict aliasing can cause some parts
 #       of Ghostscript to malfunction.
 # --------------------------------------------------
-if test $ac_cv_prog_gcc = yes; then
+if test $GCC = yes; then
   AC_MSG_CHECKING([whether to explicitly disable strict aliasing])
   CFLAGS_backup="$CFLAGS"
   CFLAGS="$CFLAGS -fno-strict-aliasing"