Use external libs of static libraries when the static library is linked to a final target.

ninjabackend.py

@@ -1252,6 +1252,10 @@ rule FORTRAN_DEP_HACK
         if not(isinstance(target, build.StaticLibrary)):
             for dep in target.get_external_deps():
                 commands += dep.get_link_args()
+        for d in target.get_dependencies():
+            if isinstance(d, build.StaticLibrary):
+                for dep in d.get_external_deps():
+                    commands += dep.get_link_args()
         commands += linker.build_rpath_args(self.environment.get_build_dir(),\
                                             target.get_rpaths(), target.install_rpath)
         if self.environment.coredata.coverage:

test cases/linuxlike/4 extdep static lib/lib.c

@@ -0,0 +1,8 @@
+#include<zlib.h>
+
+int statlibfunc() {
+    void * something = deflate;
+    if(something != 0)
+        return 0;
+    return 1;
+}

test cases/linuxlike/4 extdep static lib/meson.build

@@ -0,0 +1,10 @@
+project('external dependency with static', 'c')
+
+# Zlib is probably on all dev machines.
+
+dep = dependency('zlib')
+statlib = static_library('statlib', 'lib.c', dependencies : dep)
+exe = executable('prog', 'prog.c', link_with : statlib)
+
+
+test('zlibtest', exe)

test cases/linuxlike/4 extdep static lib/prog.c

@@ -0,0 +1,5 @@
+int statlibfunc();
+
+int main(int argc, char **argv) {
+    return statlibfunc();
+}