Add regression test for pch link_whole bug.

test cases/common/13 pch/linkwhole/lib1.c

@@ -0,0 +1,4 @@
+void func1() {
+    printf("Calling func2.");
+    func2();
+}

test cases/common/13 pch/linkwhole/lib2.c

@@ -0,0 +1,6 @@
+#include<stdio.h>
+
+void func2() {
+    const char *cl = GetCommandLineA();
+    printf("Command line was: %s\n", cl);
+}

test cases/common/13 pch/linkwhole/main.c

@@ -0,0 +1,9 @@
+#include<stdio.h>
+
+void func1();
+
+int main(int argc, char **argv) {
+    printf("Calling func1\n");
+    func1();
+    return 0;
+}

test cases/common/13 pch/linkwhole/meson.build

@@ -0,0 +1,8 @@
+# https://github.com/mesonbuild/meson/issues/10745
+
+l2 = static_library('two', 'lib2.c', c_pch: 'pch2/pch_two.h')
+l1 = static_library('one', 'lib1.c', c_pch: 'pch1/pch_one.h',
+  link_whole: l2)
+
+executable('linkprog', 'main.c',
+  link_with: l1)

test cases/common/13 pch/linkwhole/pch1/pch_one.h

@@ -0,0 +1,4 @@
+#ifndef PCH_ONE
+#define PCH_ONE
+#include<stdio.h>
+#endif

test cases/common/13 pch/linkwhole/pch2/pch_two.h

@@ -0,0 +1,4 @@
+#ifndef PCH_TWO
+#define PCH_TWO
+#include<windows.h>
+#endif

test cases/common/13 pch/meson.build

@@ -20,3 +20,7 @@ if meson.backend() == 'xcode'
 else
   subdir('mixed')
 endif
+
+if cc_id == 'msvc'
+  subdir('linkwhole')
+endif