[PATCH 3/4] configure: Try to figure out compiler options

[Dennis Stosberg <dennis@stosberg.net>]

From: Dennis Stosberg <dennis@stosberg.net>

This patch adds tests to determine of what flavour the used
compiler is and sets CFLAGS and the PIC flag appropriately.

Signed-off-by: Dennis Stosberg <dennis@stosberg.net>
---

 Makefile      |    3 ++-
 config-lib.sh |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 4dc5379..23c784e 100644
--- a/Makefile
+++ b/Makefile
@@ -96,6 +96,7 @@ ALL_CFLAGS = $(CFLAGS)
 ALL_LDFLAGS = $(LDFLAGS)
 PERL_CFLAGS =
 PERL_LDFLAGS =
+PICFLAG = -fPIC
 STRIP ?= strip
 
 prefix = $(HOME)
@@ -483,7 +484,7 @@ endif
 endif
 endif
 ifdef USE_PIC
-	ALL_CFLAGS += -fPIC
+	ALL_CFLAGS += $(PICFLAG)
 endif
 ifdef NO_ACCURATE_DIFF
 	BASIC_CFLAGS += -DNO_ACCURATE_DIFF
diff --git a/config-lib.sh b/config-lib.sh
index 3968245..0bcd4c3 100755
--- a/config-lib.sh
+++ b/config-lib.sh
@@ -35,9 +35,9 @@ compile_check() {
 	echo
 	cat "$1"
 	echo
-	echo "$_cc $CFLAGS $_inc_extra $_ld_static $_ld_extra -o $TMPO $@"
+	echo "$_cc $_cflags $_inc_extra $_ld_static $_ld_extra -o $TMPO $@"
 	rm -f "$TMPO"
-	$_cc $CFLAGS $_inc_extra $_ld_static $_ld_extra -o "$TMPO" "$@" || return $?
+	$_cc $_cflags $_inc_extra $_ld_static $_ld_extra -o "$TMPO" "$@" || return $?
 	echo
 	echo "ldd $TMPO"
 	$_ldd "$TMPO" || return $?
@@ -283,7 +283,7 @@ Installation directories:
   --gitpythondir=DIR     use this prefix for python libraries [PREFIX/share/git-core/python]
 
 Miscellaneous options:
-  --cc=COMPILER          use this C compiler to build MPlayer [gcc]
+  --cc=COMPILER          use this C compiler to build Git [cc]
   --perl=PATH            path to perl binary [autodetect]
   --python=PATH          path to python binary [autodetect]
   --target=PLATFORM      target platform (i386-linux, arm-linux, etc)
@@ -373,8 +373,8 @@ EOF
 				i[3-9]86*|x86|x86pc|k5|k6|k6_2|k6_3|k6-2|k6-3|pentium*|athlon*|i586_i686|i586-i686|BePC) host_arch=i386 ;;
 				ia64) host_arch=ia64 ;;
 				x86_64|amd64)
-				if [ -n "`$_cc -dumpmachine | sed -n '/^x86_64-/p;/^amd64-/p'`" -a \
-					-z "`echo $CFLAGS | grep -- -m32`"  ]; then
+				if [ -n "`$_cc -dumpmachine 2>/dev/null | sed -n '/^x86_64-/p;/^amd64-/p'`" -a \
+					-z "`echo $_cflags | grep -- -m32`"  ]; then
 					host_arch=x86_64
 				else
 					host_arch=i386
@@ -430,7 +430,51 @@ test_setup() {
 	TMPS="$I/git-conf-$RANDOM-$$.S"
 }
 
+cc_flavour() {
+
+	echocheck "whether cc is GCC"
+	cat > $TMPC <<EOF
+#ifndef __GNUC__
+#error Not GCC
+#endif
+int main(void) { return 0; }
+EOF
+	if cc_check ; then
+		echores "yes"
+		_cc_flavour="gcc"
+		return
+	fi
+	echores "no"
+
+	echocheck "whether cc is Sun CC"
+	cat > $TMPC <<EOF
+#ifndef __SUNPRO_C
+#error Not SUN CC
+#endif
+int main(void) { return 0; }
+EOF
+	if cc_check ; then
+		echores "yes"
+		_cc_flavour="suncc"
+		return
+	fi
+	echores "no"
+}
+
 basic_tests() {
+	_cc_flavour=unknown
+	cc_flavour
+
+	if test "$_cc_flavour" = "gcc" ; then
+		_cflags="-g -O2 -Wall"
+		_picflag="-fPIC"
+	elif test "$_cc_flavour" = "suncc"; then
+		_cflags="-g -xO3"
+		_picflag="-KPIC"
+	fi
+	test "$CFLAGS" && _cflags="$CFLAGS"
+	test "$PICFLAG" && _picflag="$PICFLAG"
+
 	echocheck "if your build environment is sane"
 	cat > $TMPC <<EOF
 int main(void) { return 0; }
@@ -483,6 +527,8 @@ write_config() {
 # -------- Generated by configure -----------
 
 CC = $_cc
+CFLAGS = $_cflags
+PICFLAG = $_picflag
 PERL_PATH = $_perl
 INSTALL = $_install