toolchain-external: support toolchains with lib32 directories

Some toolchains, like the Cavium Networks' one, have lib32/ and lib64/
directories, while the standard lib/ is empty. To find libc.a, buildroot
currently only looks in lib/ and lib64/. This patch extends the search
to lib32/ as well.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

toolchain/toolchain-external/ext-tool.mk

@@ -363,7 +363,7 @@ $(STAMP_DIR)/ext-toolchain-checked: $(TOOLCHAIN_EXTERNAL_DEPENDENCIES)
 	@$(call MESSAGE,"Checking external toolchain settings")
 	$(Q)$(call check_cross_compiler_exists,$(TOOLCHAIN_EXTERNAL_CC))
 	$(Q)LIBC_A_LOCATION=`readlink -f $$(LANG=C $(TOOLCHAIN_EXTERNAL_CC) -print-file-name=libc.a)` ; \
-	SYSROOT_DIR=`echo $${LIBC_A_LOCATION} | sed -r -e 's:usr/lib(64)?/(.*/)?libc\.a::'` ; \
+	SYSROOT_DIR=`echo $${LIBC_A_LOCATION} | sed -r -e 's:usr/lib(32|64)?/(.*/)?libc\.a::'` ; \
 	if test -z "$${SYSROOT_DIR}" ; then \
 		@echo "External toolchain doesn't support --sysroot. Cannot use." ; \
 		exit 1 ; \
@@ -397,7 +397,7 @@ $(STAMP_DIR)/ext-toolchain-checked: $(TOOLCHAIN_EXTERNAL_DEPENDENCIES)
 #
 #  SYSROOT_DIR:         the main sysroot directory, deduced from
 #                       LIBC_A_LOCATION by removing the
-#                       usr/lib[64]/libc.a part of the path.
+#                       usr/lib[32|64]/libc.a part of the path.
 #                       Ex: /x-tools/mips-2011.03/mips-linux-gnu/libc/
 #
 # ARCH_LIBC_A_LOCATION: location of the libc.a file in the selected
@@ -408,11 +408,11 @@ $(STAMP_DIR)/ext-toolchain-checked: $(TOOLCHAIN_EXTERNAL_DEPENDENCIES)
 #
 # ARCH_SYSROOT_DIR:     the sysroot of the selected multilib variant,
 #                       deduced from ARCH_LIBC_A_LOCATION by removing
-#                       usr/lib[64]/libc.a at the end of the path.
+#                       usr/lib[32|64]/libc.a at the end of the path.
 #                       Ex: /x-tools/mips-2011.03/mips-linux-gnu/libc/mips16/soft-float/el/
 #
-# ARCH_LIB_DIR:         'lib' or 'lib64' depending on where libraries are
-#                       stored. Deduced from ARCH_LIBC_A_LOCATION by
+# ARCH_LIB_DIR:         'lib', 'lib32' or 'lib64' depending on where libraries
+#                       are stored. Deduced from ARCH_LIBC_A_LOCATION by
 #                       looking at usr/lib??/libc.a.
 #                       Ex: lib
 #
@@ -433,14 +433,14 @@ $(STAMP_DIR)/ext-toolchain-checked: $(TOOLCHAIN_EXTERNAL_DEPENDENCIES)
 
 $(STAMP_DIR)/ext-toolchain-installed: $(STAMP_DIR)/ext-toolchain-checked
 	$(Q)LIBC_A_LOCATION=`readlink -f $$(LANG=C $(TOOLCHAIN_EXTERNAL_CC) -print-file-name=libc.a)` ; \
-	SYSROOT_DIR=`echo $${LIBC_A_LOCATION} | sed -r -e 's:usr/lib(64)?/(.*/)?libc\.a::'` ; \
+	SYSROOT_DIR=`echo $${LIBC_A_LOCATION} | sed -r -e 's:usr/lib(32|64)?/(.*/)?libc\.a::'` ; \
 	if test -z "$${SYSROOT_DIR}" ; then \
 		@echo "External toolchain doesn't support --sysroot. Cannot use." ; \
 		exit 1 ; \
 	fi ; \
 	ARCH_LIBC_A_LOCATION=`readlink -f $$(LANG=C $(TOOLCHAIN_EXTERNAL_CC) $(TOOLCHAIN_EXTERNAL_CFLAGS) -print-file-name=libc.a)` ; \
-	ARCH_SYSROOT_DIR=`echo $${ARCH_LIBC_A_LOCATION} | sed -r -e 's:usr/lib(64)?/(.*/)?libc\.a::'` ; \
-	ARCH_LIB_DIR=`echo $${ARCH_LIBC_A_LOCATION} | sed -r -e 's:.*/usr/(lib(64)?)/(.*/)?libc.a:\1:'` ; \
+	ARCH_SYSROOT_DIR=`echo $${ARCH_LIBC_A_LOCATION} | sed -r -e 's:usr/lib(32|64)?/(.*/)?libc\.a::'` ; \
+	ARCH_LIB_DIR=`echo $${ARCH_LIBC_A_LOCATION} | sed -r -e 's:.*/usr/(lib(32|64)?)/(.*/)?libc.a:\1:'` ; \
 	SUPPORT_LIB_DIR="" ; \
 	if test `find $${ARCH_SYSROOT_DIR} -name 'libstdc++.a' | wc -l` -eq 0 ; then \
 		LIBSTDCPP_A_LOCATION=$$(LANG=C $(TOOLCHAIN_EXTERNAL_CC) $(TOOLCHAIN_EXTERNAL_CFLAGS) -print-file-name=libstdc++.a) ; \
@@ -489,8 +489,8 @@ $(STAMP_DIR)/ext-toolchain-bfin-fdpic-shared-installed: $(STAMP_DIR)/ext-toolcha
 	$(Q)$(call MESSAGE,"Install external toolchain FDPIC libraries to target...") ; \
 	FDPIC_EXTERNAL_CC=$(dir $(TOOLCHAIN_EXTERNAL_CC))/../../bfin-linux-uclibc/bin/bfin-linux-uclibc-gcc ; \
 	FDPIC_LIBC_A_LOCATION=`readlink -f $$(LANG=C $${FDPIC_EXTERNAL_CC} $(TOOLCHAIN_EXTERNAL_CFLAGS) -print-file-name=libc.a)` ; \
-	FDPIC_SYSROOT_DIR=`echo $${FDPIC_LIBC_A_LOCATION} | sed -r -e 's:usr/lib(64)?/(.*/)?libc\.a::'` ; \
-	FDPIC_LIB_DIR=`echo $${FDPIC_LIBC_A_LOCATION} | sed -r -e 's:.*/usr/(lib(64)?)/(.*/)?libc.a:\1:'` ; \
+	FDPIC_SYSROOT_DIR=`echo $${FDPIC_LIBC_A_LOCATION} | sed -r -e 's:usr/lib(32|64)?/(.*/)?libc\.a::'` ; \
+	FDPIC_LIB_DIR=`echo $${FDPIC_LIBC_A_LOCATION} | sed -r -e 's:.*/usr/(lib(32|64)?)/(.*/)?libc.a:\1:'` ; \
 	FDPIC_SUPPORT_LIB_DIR="" ; \
 	if test `find $${FDPIC_SYSROOT_DIR} -name 'libstdc++.a' | wc -l` -eq 0 ; then \
 	        FDPIC_LIBSTDCPP_A_LOCATION=$$(LANG=C $${FDPIC_EXTERNAL_CC} $(TOOLCHAIN_EXTERNAL_CFLAGS) -print-file-name=libstdc++.a) ; \