configure: Check llvm-config --shared-mode

https://bugs.llvm.org/show_bug.cgi?id=6823 still affects current LLVM.
llvm-config --libs only reports the single shared library if LLVM was
built with -DLLVM_LINK_LLVM_DYLIB=ON. llvm-config --shared-mode reports
"shared" in that case, "static" otherwise (even if LLVM was built with
-DLLVM_BUILD_LLVM_DYLIB=ON).

v2: Keep the LLVM < 4.0 test. (llvm-config --shared-mode is actually
    available since LLVM 3.8, but that would make the test too
    complicated :)

Fixes: 3d8da1f678e1 ("configure: Trust LLVM >= 4.0 llvm-config --libs
                      for shared libraries")
Bugzilla: https://bugs.freedesktop.org/102247
Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de>

diff --git a/configure.ac b/configure.ac
index e3babd3909aeea3081c0b3d2a13f9735c5364285..52645bb44ff64e3ab48c7c0c45c6009926db4d88 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -2646,7 +2646,7 @@ if test "x$enable_llvm" = xyes; then
     LLVM_LIBS="`$LLVM_CONFIG --libs ${LLVM_COMPONENTS}`"
 
     if test "x$enable_llvm_shared_libs" = xyes; then
-        if test $LLVM_VERSION_MAJOR -lt 4; then
+        if test $LLVM_VERSION_MAJOR -lt 4 -o "`$LLVM_CONFIG --shared-mode ${LLVM_COMPONENTS}`" = static; then
             dnl llvm-config may not give the right answer when llvm is a built as a
             dnl single shared library, so we must work the library name out for
             dnl ourselves.