Make sure that __malloc_hook functions are exported from the library.

This is required to make mixed build types (asan + regular build) work properly.
See DEVTOOLSSUPPORT-88738 for the details.
--- a/include/jemalloc/internal/jemalloc_internal_defs-linux.h	(989d5f3fa2d340cd2931b54d12f09f580991116d)
+++ b/include/jemalloc/internal/jemalloc_internal_defs-linux.h	(0d8b9317f37ded4b37d7db4aab938e75843b65c4)
@@ -370,1 +370,1 @@
-/* #undef JEMALLOC_GLIBC_MALLOC_HOOK */
+#define JEMALLOC_GLIBC_MALLOC_HOOK 
@@ -370,1 +370,1 @@
-/* #undef JEMALLOC_GLIBC_MEMALIGN_HOOK */
+#define JEMALLOC_GLIBC_MEMALIGN_HOOK