contrib: Fix a bug in the old gmp configure script

The brackets in the config test aren't properly escaped, and thus
don't end up in the final configure script as intended.

When building on a system where the system default compiler is clang,
clang can fail due to the main signature
"int main(int argc, char *argv)" being invalid,
which makes configure believe that the system compiler isn't
ANSI compliant, and it tries to invoke (broken) ANSI2KNR code.
Signed-off-by: Martin Storsjö <martin@martin.st>

contrib/src/gmp/ansitest.diff

+--- gmp-4.2.1/acinclude.m4.orig	2013-04-01 22:50:05.000000000 +0300
++++ gmp-4.2.1/acinclude.m4	2013-04-01 22:49:52.000000000 +0300
+@@ -3765,7 +3765,7 @@
+                gmp_cv_c_for_build_ansi,
+ [cat >conftest.c <<EOF
+ int
+-main (int argc, char *argv[])
++main (int argc, char **argv)
+ {
+   exit(0);
+ }

contrib/src/gmp/rules.mak

@@ -14,10 +14,11 @@ $(TARBALLS)/gmp-$(GMP_VERSION).tar.bz2:
 gmp: gmp-$(GMP_VERSION).tar.bz2 .sum-gmp
 	$(UNPACK)
 	$(APPLY) $(SRC)/gmp/inline.diff
-	$(UPDATE_AUTOCONFIG)
+	$(APPLY) $(SRC)/gmp/ansitest.diff
 	$(MOVE)
 
 .gmp: gmp
+	$(RECONF)
 	cd $< && $(HOSTVARS) ./configure $(HOSTCONF)
 	cd $< && $(MAKE) install
 	touch $@