From: Hilko Bengen <bengen@debian.org>
Date: Tue, 22 Jan 2019 18:10:47 +0100
Subject: configure: Introduce CLANG variable

---
 configure.ac | 9 +++++++++
 1 file changed, 9 insertions(+)

--- a/configure.ac
+++ b/configure.ac
@@ -38,6 +38,15 @@
 
     AC_SUBST([CLANG])
 
+    AC_ARG_WITH([clang],
+                [CLANG compiler],
+                [CLANG="$withval"],
+                [AS_IF([test "$compiler" = clang],
+                       [CLANG="$CC"],
+                       [AC_PATH_PROG([CLANG],[clang])])])
+
+    AC_SUBST([CLANG])
+
     case "$compiler" in
         clang)
             CLANG_CFLAGS="-Wextra -Werror-implicit-function-declaration -Wno-error=unused-command-line-argument"