Fix build with musl libc 1.2.4

Musl 1.2.4 gated the LFS64 compatibility shims behind the
_LARGEFILE64_SOURCE macro, and they will be removed entirely in musl
1.2.5. Use stat64 only when __GLIBC__ is defined.

Signed-off-by: Violet Purcell <vimproved@inventati.org>

source/modules/water/files/File.cpp

@@ -1265,7 +1265,7 @@ class DirectoryIterator::NativeIterator::Pimpl
 //=====================================================================================================================
 namespace
 {
-   #ifdef CARLA_OS_LINUX
+   #ifdef __GLIBC__
     typedef struct stat64 water_statStruct;
     #define WATER_STAT    stat64
    #else