Stefan Fiedler:

package/base/glibc/glibc.conf

@@ -114,6 +114,13 @@ if [ "$pkg_glibc_cross" ] ; then
 	fi
 fi
 
+# Fix for mips when building glibc headers.
+if [[ "$pkg_glibc_host" == mips* ]] ; then
+	if [ $pkg_glibc_headers_only = 1 ] ; then
+		var_append patchfiles " " "$confdir/glibc$pkg_glibc_version/glibc-*-mips-mabi-stage0.diff"
+	fi
+fi
+
 hook_add prepatch 5 "glibc_prepatch"
 glibc_prepatch () {
 	echo Extracting $archdir/glibc-ports-*.tar.bz2 ...

package/base/glibc/glibc27/glibc-2.7-mips-mabi-stage0.diff

@@ -0,0 +1,14 @@
+In stage 0 glibc configure tries to call the build system gcc with -mabi=32,
+causing test failures. Also set _MIPS_SZPTR for 32bit builds since it is not
+defined elsewhere.
+
+See http://sourceware.org/ml/crossgcc/2005-07/msg00036.html and
+http://sourceware.org/ml/crossgcc/2008-01/msg00007.html
+
+--- glibc-2.7/ports/sysdeps/mips/mips32/Makefile-orig	2003-03-29 09:15:28.000000000 +0100
++++ glibc-2.7/ports/sysdeps/mips/mips32/Makefile	2008-10-06 03:29:36.000000000 +0200
+@@ -1,3 +1,3 @@
+ ifeq ($(filter -mabi=32,$(CC)),)
+-CC += -mabi=32
++CC += -D"_MIPS_SZPTR=32"
+ endif