fix static builds of zig from requiring c compiler

to be installed when linking libc.

When zig links against libc, it requires a dynamic linker path.
Usually this can be determined based on the architecture and operating
system components of the target. However on some systems this is not
correct; because of this zig checks its own dynamic linker.

When zig is statically linked, this information is not available, and so
it resorts to using cc -print-filename=foo to find the dynamic linker
path.

Before this commit, Zig incorrectly exited with an error if there was
no c compiler installed. Now, Zig falls back to the dynamic linker
determined based on the arch and os when no C compiler can be found.

1 files changed, 14 insertions, 4 deletions

diff --git a/src/os.cpp b/src/os.cpp
index 83c67d5818..8ab5007d80 100644
--- a/src/os.cpp
+++ b/src/os.cpp
@@ -791,6 +791,7 @@ static Error os_exec_process_posix(const char *exe, ZigList<const char *> &args,
     int stdin_pipe[2];
     int stdout_pipe[2];
     int stderr_pipe[2];
+    int err_pipe[2];
 
     int err;
     if ((err = pipe(stdin_pipe)))
@@ -799,6 +800,8 @@ static Error os_exec_process_posix(const char *exe, ZigList<const char *> &args,
         zig_panic("pipe failed");
     if ((err = pipe(stderr_pipe)))
         zig_panic("pipe failed");
+    if ((err = pipe(err_pipe)))
+        zig_panic("pipe failed");
 
     pid_t pid = fork();
     if (pid == -1)
@@ -821,11 +824,12 @@ static Error os_exec_process_posix(const char *exe, ZigList<const char *> &args,
             argv[i + 1] = args.at(i);
         }
         execvp(exe, const_cast<char * const *>(argv));
+        Error report_err = ErrorUnexpected;
         if (errno == ENOENT) {
-            return ErrorFileNotFound;
-        } else {
-            zig_panic("execvp failed: %s", strerror(errno));
+            report_err = ErrorFileNotFound;
         }
+        write(err_pipe[1], &report_err, sizeof(Error));
+        exit(1);
     } else {
         // parent
         close(stdin_pipe[0]);
@@ -847,7 +851,13 @@ static Error os_exec_process_posix(const char *exe, ZigList<const char *> &args,
 
         if (err1) return err1;
         if (err2) return err2;
-        return ErrorNone;
+
+        Error child_err = ErrorNone;
+        write(err_pipe[1], &child_err, sizeof(Error));
+        close(err_pipe[1]);
+        read(err_pipe[0], &child_err, sizeof(Error));
+        close(err_pipe[0]);
+        return child_err;
     }
 }
 #endif