[rcore][android] Add WARNING comment for --wrap=fopen build system requirements (#5624)

Co-authored-by: Federico Gherardi <ghera@libero.it>

src/platforms/rcore_android.c

@@ -275,6 +275,22 @@ static int android_write(void *cookie, const char *buf, int size);
 static fpos_t android_seek(void *cookie, fpos_t offset, int whence);
 static int android_close(void *cookie);
 
+// WARNING: fopen() calls are intercepted via linker flag -Wl,--wrap=fopen: the linker renames
+// the original fopen -> __real_fopen and redirects all call sites to __wrap_fopen
+// The flag MUST be applied at every final link step that needs wrapping,
+// it has no effect when only building a static archive (.a)
+//
+//         CMake: no action required, raylib's CMakeLists.txt already sets 
+//                target_link_options(raylib INTERFACE -Wl,--wrap=fopen) which propagates to
+//                the final app link, wrapping app code and all static (.a) dependencies too
+// Make (SHARED): no action required for raylib itself, src/Makefile already sets 
+//                LDFLAGS += -Wl,--wrap=fopen wrapping fopen inside libraylib.so only;
+//                app code and static (.a) dependencies are NOT wrapped unless -Wl,--wrap=fopen
+//                is also added to the final app link step
+// Make (STATIC): pass -Wl,--wrap=fopen to the linker command producing the final artifact
+//     build.zig: no dedicated wrap helper; pass -Wl,--wrap=fopen to the linker command producing 
+//                the final artifact
+//        custom: pass -Wl,--wrap=fopen to the linker command producing the final artifact
 FILE *__real_fopen(const char *fileName, const char *mode); // Real fopen, provided by the linker (--wrap=fopen)
 FILE *__wrap_fopen(const char *fileName, const char *mode); // Replacement for fopen()