Explicitly call '/usr/bin/arch' instead of just 'arch' to avoid using

a user-installed version of arch instead of the intended version. This is
needed because the interface of GNU arch is not quite compatible with what
the build machinery expects.

Fixes issue #7715 (backport from the trunk)

configure

 #! /bin/sh
-# From configure.in Revision: 78065 .
+# From configure.in Revision: 78069 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for python 2.6.
 #
@@ -4699,15 +4699,15 @@ echo "${ECHO_T}$ac_cv_no_strict_aliasing_ok" >&6; }
 
 	         elif test "$UNIVERSAL_ARCHS" = "all" ; then
 		   UNIVERSAL_ARCH_FLAGS="-arch i386 -arch ppc -arch ppc64 -arch x86_64"
-		   ARCH_RUN_32BIT="arch -i386 -ppc"
+		   ARCH_RUN_32BIT="/usr/bin/arch -i386 -ppc"
 
 	         elif test "$UNIVERSAL_ARCHS" = "intel" ; then
 		   UNIVERSAL_ARCH_FLAGS="-arch i386 -arch x86_64"
-		   ARCH_RUN_32BIT="arch -i386"
+		   ARCH_RUN_32BIT="/usr/bin/arch -i386"
 
 	         elif test "$UNIVERSAL_ARCHS" = "3-way" ; then
 		   UNIVERSAL_ARCH_FLAGS="-arch i386 -arch ppc -arch x86_64"
-		   ARCH_RUN_32BIT="arch -i386 -ppc"
+		   ARCH_RUN_32BIT="/usr/bin/arch -i386 -ppc"
 
 		 else
 	           { { echo "$as_me:$LINENO: error: proper usage is --with-universal-arch=32-bit|64-bit|all|intel|3-way" >&5

configure.in

@@ -950,15 +950,15 @@ yes)
 
 	         elif test "$UNIVERSAL_ARCHS" = "all" ; then
 		   UNIVERSAL_ARCH_FLAGS="-arch i386 -arch ppc -arch ppc64 -arch x86_64"
-		   ARCH_RUN_32BIT="arch -i386 -ppc"
+		   ARCH_RUN_32BIT="/usr/bin/arch -i386 -ppc"
 
 	         elif test "$UNIVERSAL_ARCHS" = "intel" ; then
 		   UNIVERSAL_ARCH_FLAGS="-arch i386 -arch x86_64"
-		   ARCH_RUN_32BIT="arch -i386"
+		   ARCH_RUN_32BIT="/usr/bin/arch -i386"
 
 	         elif test "$UNIVERSAL_ARCHS" = "3-way" ; then
 		   UNIVERSAL_ARCH_FLAGS="-arch i386 -arch ppc -arch x86_64"
-		   ARCH_RUN_32BIT="arch -i386 -ppc"
+		   ARCH_RUN_32BIT="/usr/bin/arch -i386 -ppc"
 
 		 else
 	           AC_MSG_ERROR([proper usage is --with-universal-arch=32-bit|64-bit|all|intel|3-way])