configure.ac: Test for -ffunction-sections -fdata-sections and set SECTION_FLAGS accordingly.

	* configure.ac: Test for -ffunction-sections -fdata-sections and
	set SECTION_FLAGS accordingly.
	* configure: Regenerate.

	* Makefile.am: Add SECTION_FLAGS to AM_CFLAGS.
	* Makefile.in: Regenerate.

From-SVN: r146241

libgfortran/ChangeLog

+2009-04-17  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>
+
+	* configure.ac: Test for -ffunction-sections -fdata-sections and
+	set SECTION_FLAGS accordingly.
+	* configure: Regenerate.
+
+	* Makefile.am: Add SECTION_FLAGS to AM_CFLAGS.
+	* Makefile.in: Regenerate.
+
 2009-04-15  Janne Blomqvist  <jb@gcc.gnu.org>
 
 	PR libfortran/38668

libgfortran/Makefile.am

@@ -33,6 +33,10 @@ AM_CPPFLAGS = -iquote$(srcdir)/io -I$(srcdir)/$(MULTISRCTOP)../gcc \
 # Fortran rules for complex multiplication and division
 AM_CFLAGS += -fcx-fortran-rules
 
+# Use -ffunction-sections -fdata-sections if supported by the compiler
+SECTION_FLAGS = @SECTION_FLAGS@
+AM_CFLAGS += $(SECTION_FLAGS)
+
 gfor_io_src= \
 io/close.c \
 io/file_pos.c \

libgfortran/Makefile.in

@@ -815,7 +815,7 @@ AMDEP_TRUE = @AMDEP_TRUE@
 AMTAR = @AMTAR@
 
 # Fortran rules for complex multiplication and division
-AM_CFLAGS = @AM_CFLAGS@ -fcx-fortran-rules
+AM_CFLAGS = @AM_CFLAGS@ -fcx-fortran-rules $(SECTION_FLAGS)
 AM_FCFLAGS = @AM_FCFLAGS@
 AR = @AR@
 AS = @AS@
@@ -875,6 +875,9 @@ PACKAGE_TARNAME = @PACKAGE_TARNAME@
 PACKAGE_VERSION = @PACKAGE_VERSION@
 PATH_SEPARATOR = @PATH_SEPARATOR@
 RANLIB = @RANLIB@
+
+# Use -ffunction-sections -fdata-sections if supported by the compiler
+SECTION_FLAGS = @SECTION_FLAGS@
 SED = @SED@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@

libgfortran/configure.ac

@@ -149,6 +149,27 @@ LDFLAGS="$save_LDFLAGS"
 AC_MSG_RESULT($gfortran_use_symver)
 AM_CONDITIONAL(LIBGFOR_USE_SYMVER, [test "x$gfortran_use_symver" = xyes])
 
+# Figure out whether the compiler supports "-ffunction-sections -fdata-sections",
+# similarly to how libstdc++ does it
+ac_test_CFLAGS="${CFLAGS+set}"
+ac_save_CFLAGS="$CFLAGS"
+
+# Check for -ffunction-sections -fdata-sections
+AC_MSG_CHECKING([for gcc that supports -ffunction-sections -fdata-sections])
+CFLAGS='-Werror -ffunction-sections -fdata-sections'
+AC_TRY_COMPILE(, [int foo;], [ac_fdsections=yes], [ac_fdsections=no])
+if test "$ac_test_CFLAGS" = set; then
+  CFLAGS="$ac_save_CFLAGS"
+else
+  # this is the suspicious part
+  CFLAGS=""
+fi
+if test x"$ac_fdsections" = x"yes"; then
+  SECTION_FLAGS='-ffunction-sections -fdata-sections'
+fi
+AC_MSG_RESULT($ac_fdsections)
+AC_SUBST(SECTION_FLAGS)
+
 # Find other programs we need.
 AC_CHECK_TOOL(AS, as)
 AC_CHECK_TOOL(AR, ar)