ash: special hack for libtool

Libtool assumes the host environment is MSYS2 and will be confused by
Windows-style command switches. The "/c" in "cmd /c" looks like a path,
which MSYS2 incorrectly decodes to "c:/". Anticipating this, libtool
encodes these calls as "cmd //c" which does not work outside MSYS2. A
busybox-w32 patch makes it behave like MSYS2 in just this one case.

Adds 88-96 bytes.

(GitHub issue #297 and https://github.com/skeeto/w64devkit/issues/50)

1 files changed, 10 insertions, 0 deletions

diff --git a/shell/ash.c b/shell/ash.c
index b894a2314..e2dcb0962 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9142,6 +9142,16 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) const char *cmd, char **argv, c
 #endif
 
 #if ENABLE_PLATFORM_MINGW32
+        /* Workaround for libtool, which assumes the host is an MSYS2
+         * environment and requires special-case escaping for cmd.exe.
+         * https://github.com/skeeto/w64devkit/issues/50 */
+        if (string_array_len(argv) >= 3 &&
+                        strcmp(argv[0], "cmd") == 0 &&
+                        strcmp(argv[1], "//c") == 0 &&
+                        strcmp(argv[2], "echo") == 0) {
+                argv[1]++;      /* drop extra slash */
+        }
+
         /* cmd was allocated on the stack with room for an extension */
         add_win32_extension((char *)cmd);
         execve(cmd, argv, envp);