Move the AC_PROG_CC checks earlier in the configure file. The lateness

of the original check meant that configure was caching the default
CC check and using that instead of the result of AC_PROG_CC in both
configure checks and during compilation.

This wasn't affecting C++ so it was hard to notice.

Regenerate configure.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139937 91177308-0d34-0410-b5e6-96231b3b80d8

autoconf/configure.ac

@@ -58,6 +58,12 @@ if test ${srcdir} != "." ; then
   fi
 fi
 
+dnl We need to check for the compiler up here to avoid anything else
+dnl starting with a different one.
+AC_PROG_CC(clang llvm-gcc gcc)
+AC_PROG_CXX(clang++ llvm-g++ g++)
+AC_PROG_CPP
+
 dnl Configure all of the projects present in our source tree. While we could
 dnl just AC_CONFIG_SUBDIRS on the set of directories in projects that have a
 dnl configure script, that usage of the AC_CONFIG_SUBDIRS macro is deprecated.
@@ -965,11 +971,6 @@ dnl=== SECTION 4: Check for programs we need and that they are the right version
 dnl===
 dnl===-----------------------------------------------------------------------===
 
-dnl Check for compilation tools
-AC_PROG_CPP
-AC_PROG_CC(clang llvm-gcc gcc)
-AC_PROG_CXX(clang++ llvm-g++ g++)
-
 AC_PROG_NM
 AC_SUBST(NM)