From: Graham Percival <graham@percival-music.ca>
Date: Mon, 28 Nov 2011 09:08:40 +0000 (-0800)
Subject: Build: don't check gcc version numbers with clang
X-Git-Tag: release/2.15.21-1~17
X-Git-Url: https://git.donarmstrong.com/?a=commitdiff_plain;h=2b76b924d478e68baaacfca52c6819d4c15b4c56;p=lilypond.git

Build: don't check gcc version numbers with clang

Joy, this was totally worth an hour.  :(   I hate build systems.
---

diff --git a/configure.in b/configure.in
index f7638ad389..74a27bbfa8 100644
--- a/configure.in
+++ b/configure.in
@@ -91,10 +91,14 @@ AC_MSG_RESULT($NCSB_SOURCE_FILES)
 AC_LANG([C++])
 
 STEPMAKE_PYTHON(REQUIRED, 2.4)
-STEPMAKE_GCC(REQUIRED, 3.4)
+# this checks if we have GNU C by compiling a program with
+# __GNUC__, but that macro now unofficially means "the compiler
+# supports the GNU C extensions" -- the intel C compiler and clang
+# both support __GNUC__!
+STEPMAKE_GCC_OR_CLANG(REQUIRED, 3.4)
 
 STEPMAKE_CXX(REQUIRED)
-STEPMAKE_GXX(REQUIRED, 3.4)
+STEPMAKE_GXX_OR_CLANG(REQUIRED, 3.4)
 STEPMAKE_CXXTEMPLATE
 STEPMAKE_STL_DATA_METHOD
 STEPMAKE_LIB(REQUIRED)
diff --git a/stepmake/aclocal.m4 b/stepmake/aclocal.m4
index 8fe2dddb72..c29621b409 100644
--- a/stepmake/aclocal.m4
+++ b/stepmake/aclocal.m4
@@ -494,13 +494,17 @@ EOF
         AC_MSG_RESULT($FLEXLEXER_FILE)
 ])
 
-AC_DEFUN(STEPMAKE_GCC, [
-    if test "$GCC" = "yes"; then
-        STEPMAKE_CHECK_VERSION(CC, $1, $2)
-    else
-	warn="$CC (Please install *GNU* cc)"
-	STEPMAKE_ADD_ENTRY($1, $warn)
+AC_DEFUN(STEPMAKE_GCC_OR_CLANG, [
+    STEPMAKE_HAS_CLANG()
+    if test "$HAS_CLANG" = "no"; then
+        if test "$GCC" = "yes"; then
+            STEPMAKE_CHECK_VERSION(CC, $1, $2)
+        else
+	    warn="$CC (Please install *GNU* cc)"
+	    STEPMAKE_ADD_ENTRY($1, $warn)
+        fi
     fi
+    # no else, we're fine with any clang
 ])
 
 AC_DEFUN(STEPMAKE_GETTEXT, [
@@ -616,13 +620,25 @@ AC_DEFUN(STEPMAKE_DLOPEN, [
     AC_CHECK_FUNCS(dlopen)
 ])
 
-AC_DEFUN(STEPMAKE_GXX, [
-    if test "$GXX" = "yes"; then
-        STEPMAKE_CHECK_VERSION(CXX, $1, $2)
-    else
-	warn="$CXX (Please install *GNU* c++)"
-	STEPMAKE_ADD_ENTRY($1, $warn)
+AC_DEFUN(STEPMAKE_HAS_CLANG, [
+    AC_EGREP_CPP(yes,
+      [#ifdef __clang__
+       yes
+       #endif
+      ], HAS_CLANG=yes, HAS_CLANG=no)
+])
+
+AC_DEFUN(STEPMAKE_GXX_OR_CLANG, [
+    STEPMAKE_HAS_CLANG()
+    if test "$HAS_CLANG" = "no"; then
+        if test "$GXX" = "yes"; then
+            STEPMAKE_CHECK_VERSION(CXX, $1, $2)
+        else
+	    warn="$CXX (Please install *GNU* c++)"
+	    STEPMAKE_ADD_ENTRY($1, $warn)
+        fi
     fi
+    # no else, we're fine with any clang
 ])