Make build hermetic without shell scripts

- Fix some minor issues in ar.com
- Have execve() look for `ape` command
- Rewrite NT paths using /c/ rather /??/c:/
- Replace broken GCC symlinks with .sym files
- Rewrite $PATH environment variables on startup
- Make $(APE_NO_MODIFY_SELF) the default bootloader
- Add all build command dependencies to build/bootstrap
- Get the repository mostly building from source on non-Linux

test/libc/calls/clock_gettime_test.c

@@ -35,7 +35,7 @@ TEST(clock_gettime, test) {
   ASSERT_NE(0, ts.tv_sec);
   ASSERT_NE(0, ts.tv_nsec);
   if (__is_linux_2_6_23()) {
-    ASSERT_GT((intptr_t)__get_clock_gettime(&isfast),
+    ASSERT_GT((intptr_t)__clock_gettime_get(&isfast),
               getauxval(AT_SYSINFO_EHDR));
     ASSERT_TRUE(isfast);
   }

test/libc/calls/getcwd_test.c

@@ -45,5 +45,5 @@ TEST(getcwd, testWindows_addsFunnyPrefix) {
   if (!IsWindows()) return;
   char path[PATH_MAX];
   ASSERT_NE(0, getcwd(path, sizeof(path)));
-  EXPECT_STARTSWITH("//?/", path);
+  EXPECT_STARTSWITH("/C/", path);
 }

test/libc/calls/mkntenvblock_test.c

@@ -20,17 +20,18 @@
 #include "libc/runtime/gc.internal.h"
 #include "libc/testlib/testlib.h"
 
+char tmp[ARG_MAX];
 char16_t envvars[ARG_MAX / 2];
 
 TEST(mkntenvblock, emptyList_onlyOutputsDoubleNulStringTerminator) {
   char *envp[] = {NULL};
-  ASSERT_NE(-1, mkntenvblock(envvars, envp, NULL));
+  ASSERT_NE(-1, mkntenvblock(envvars, envp, NULL, tmp));
   ASSERT_BINEQ(u"  ", envvars);
 }
 
 TEST(mkntenvblock, envp_becomesSortedDoubleNulTerminatedUtf16String) {
   char *envp[] = {"u=b", "c=d", "韩=非", "uh=d", "hduc=d", NULL};
-  ASSERT_NE(-1, mkntenvblock(envvars, envp, NULL));
+  ASSERT_NE(-1, mkntenvblock(envvars, envp, NULL, tmp));
   ASSERT_BINEQ(u"C = d   "
                u"H D U C = d   "
                u"U = b   "
@@ -42,7 +43,7 @@ TEST(mkntenvblock, envp_becomesSortedDoubleNulTerminatedUtf16String) {
 
 TEST(mkntenvblock, extraVar_getsAdded) {
   char *envp[] = {"u=b", "c=d", "韩=非", "uh=d", "hduc=d", NULL};
-  ASSERT_NE(-1, mkntenvblock(envvars, envp, "a=a"));
+  ASSERT_NE(-1, mkntenvblock(envvars, envp, "a=a", tmp));
   ASSERT_BINEQ(u"A = a   "
                u"C = d   "
                u"H D U C = d   "
@@ -52,3 +53,11 @@ TEST(mkntenvblock, extraVar_getsAdded) {
                u"  ",
                envvars);
 }
+
+TEST(mkntenvblock, pathvars_getUpdated) {
+  char *envp[] = {"PATH=/c/foo:/d/bar", NULL};
+  ASSERT_NE(-1, mkntenvblock(envvars, envp, 0, tmp));
+  ASSERT_BINEQ(u"P A T H = c : \\ f o o ; d : \\ b a r   "
+               u"  ",
+               envvars);
+}

test/libc/calls/readlinkat_test.c

@@ -101,9 +101,10 @@ TEST(readlinkat, statReadsNameLength) {
 }
 
 TEST(readlinkat, realpathReturnsLongPath) {
-  if (!IsWindows()) return;
   struct stat st;
   char buf[PATH_MAX];
+  if (!IsWindows()) return;
+  if (!startswith(getcwd(buf, PATH_MAX), "/c/")) return;
   ASSERT_SYS(0, 0, touch("froot", 0644));
-  ASSERT_STARTSWITH("//?/", realpath("froot", buf));
+  ASSERT_STARTSWITH("/c/", realpath("froot", buf));
 }

test/libc/calls/test.mk

@@ -61,7 +61,7 @@ o/$(MODE)/test/libc/calls/%.com.dbg:			\
 		o/$(MODE)/test/libc/calls/calls.pkg	\
 		$(LIBC_TESTMAIN)			\
 		$(CRT)					\
-		$(APE)
+		$(APE_NO_MODIFY_SELF)
 	@$(APELINK)
 
 .PHONY: o/$(MODE)/test/libc/calls