backport from current 1.4 beta's to handle the bug where the
PNG_NO_ASSEMBLER_CODE define is not exported properly

http://bugs.gentoo.org/136346

--- libpng-1.2.12/configure.ac
+++ libpng-1.2.12/configure.ac
@@ -62,15 +62,12 @@
 AC_TRY_COMPILE(
   [#include "pnggccrd.c"],
   [return 0;],
-  LIBPNG_DEFINES=,
-  LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG\ -DPNG_NO_ASSEMBLER_CODE)
-if test "$LIBPNG_DEFINES"; then
-    AC_MSG_RESULT(no)
-else
-    AC_MSG_RESULT(yes)
-    LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG
-fi
+  [LIBPNG_NO_ASSEMBLER=yes; LIBPNG_DEFINES=""],
+  [LIBPNG_NO_ASSEMBLER=no ; LIBPNG_DEFINES="-DPNG_NO_ASSEMBLER_CODE=1"])
+LIBPNG_DEFINES="$LIBPNG_DEFINES -DPNG_CONFIGURE_LIBPNG"
+AC_MSG_RESULT($LIBPNG_NO_ASSEMBLER)
 AC_SUBST(LIBPNG_DEFINES)
+AM_CONDITIONAL(LIBPNG_NO_ASSEMBLER, test "x$LIBPNG_NO_ASSEMBLER" = "xno")
 
 AC_MSG_CHECKING([if libraries can be versioned])
 GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
--- libpng-1.2.12/Makefile.am
+++ libpng-1.2.12/Makefile.am
@@ -87,6 +87,14 @@
 
 CLEANFILES= pngout.png libpng12.pc libpng12-config libpng.vers libpng.sym

+pngconf.h: pngconf.h.in
+	sed "/Makefile-supplied defines go here:/q" pngconf.h.in > pngconf.h.tmp
+if LIBPNG_NO_ASSEMBLER
+	echo "#define PNG_NO_ASSEMBLER_CODE 1" >> pngconf.h.tmp
+endif
+	sed "1,/Makefile-supplied defines go here:/d" pngconf.h.in >> pngconf.h.tmp
+	mv pngconf.h.tmp pngconf.h
+
 $(PNGLIB_BASENAME).pc: libpng.pc
 	cp libpng.pc $@
 
--- libpng-1.2.12/pngconf.h
+++ libpng-1.2.12/pngconf.h
@@ -19,6 +19,13 @@
 
 #define PNG_1_2_X
 
+/* Backported no-assembler fix from libpng-1.4.0beta8 */
+
+/* Makefile-supplied defines go here: */
+/* End of Makefile-supplied defines. */
+
+/* End of backported no-assembler fix */
+
 /* 
  * PNG_USER_CONFIG has to be defined on the compiler command line. This
  * includes the resource compiler for Windows DLL configurations.