Workarounds for GNU Autotools (#50)

Introduce a "system-wide" profile loaded before ~/.profile, and populate
it with variables to guide GNU Autoconf. In general, "configure" scripts
should now work out-of-the-box.

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. This
patch has been upstreamed and will be removed on the next upgrade.

Author: skeeto

Dockerfile

@@ -61,7 +61,7 @@ RUN sha256sum -c $PREFIX/src/SHA256SUMS \
  && tar xzf cppcheck-$CPPCHECK_VERSION.tar.gz
 COPY src/w64devkit.c src/w64devkit.ico src/libmemory.c src/libchkstk.S \
      src/alias.c src/debugbreak.c src/pkg-config.c src/vc++filt.c \
-     src/peports.c $PREFIX/src/
+     src/peports.c src/profile $PREFIX/src/
 
 ARG ARCH=x86_64-w64-mingw32
 
@@ -504,6 +504,7 @@ RUN printf "id ICON \"$PREFIX/src/w64devkit.ico\"" >w64devkit.rc \
  && $ARCH-gcc -DEXE=pkg-config.exe -DCMD=pkg-config \
         -Os -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
         -o $PREFIX/bin/$ARCH-pkg-config.exe $PREFIX/src/alias.c -lkernel32 \
+ && sed -i s/'\<ARCH\>'/$ARCH/g $PREFIX/src/profile \
  && mkdir -p $PREFIX/$ARCH/lib/pkgconfig \
  && cp /mingw-w64-v$MINGW_VERSION/COPYING.MinGW-w64-runtime/COPYING.MinGW-w64-runtime.txt \
         $PREFIX/ \

src/busybox-003-fix-libtool.patch

@@ -0,0 +1,20 @@
+--- a/shell/ash.c
++++ b/shell/ash.c
+@@ -9142,6 +9142,17 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) const char *cmd, char **argv, c
+ #endif
+ 
+ #if ENABLE_PLATFORM_MINGW32
++	/* Workaround for libtool bug, 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);

src/busybox-004-system-profile.patch

@@ -0,0 +1,18 @@
+--- a/shell/ash.c
++++ b/shell/ash.c
+@@ -16282,7 +16282,14 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
+ 
+ 		state = 1;
+ #if ENABLE_PLATFORM_MINGW32
+-		hp = xasprintf("%s/etc/profile", get_system_drive() ?: "");
++		const char *syspath = bb_busybox_exec_path;
++		int syspathlen = 0;
++		for (int i = 0; syspath[i]; i++) {
++			if (syspath[i] == '/') {
++				syspathlen = i;
++			}
++		}
++		hp = xasprintf("%.*s/../src/profile", syspathlen, syspath);
+ 		read_profile(hp);
+ 		free((void *)hp);
+ #else

src/profile

@@ -0,0 +1,6 @@
+# GNU Autotools "configure" detects w64devkit as an MSYS2 environment, so
+# set some environment variables to disabuse it. Goes hand-in-hand with
+# the busybox-w32 ash patch for libtool.
+export PATH_SEPARATOR=';'
+export ac_executable_extensions=.exe
+export build_alias=ARCH