configure.ac: add llvm inteljitevents component if enabled

Needed to successfully link llvmpipe or swr when using shared llvm libs
built with inteljitevents enabled.

v2: Make adding inteljitevents component global rather than just
llvmpipe/swr, since libgallium will have a symbol dependency.

Cc: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/configure.ac b/configure.ac
index 0604ad9..b9e6000 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2196,6 +2196,10 @@
 
         LLVM_COMPONENTS="engine bitwriter mcjit mcdisassembler"
 
+        if $LLVM_CONFIG --components | grep -q inteljitevents ; then
+            LLVM_COMPONENTS="${LLVM_COMPONENTS} inteljitevents"
+        fi
+
         if test "x$enable_opencl" = xyes; then
             llvm_check_version_for "3" "6" "0" "opencl"