intel-clc: avoid using spirv-linker.

There is not real need to use the spirv-linker here at all,
we can just read all the CL C files into one buffer, then compile
that buffer in a single pass.

This worksaround an issue seen with llvm17 and opaque pointers
and the spirv linker.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25759>

src/intel/compiler/intel_clc.c

@@ -402,6 +402,8 @@ int main(int argc, char **argv)
       .warning = msg_callback,
    };
 
+   size_t total_size = 0;
+   char *all_inputs = NULL;
    util_dynarray_foreach(&input_files, char *, infile) {
       int fd = open(*infile, O_RDONLY);
       if (fd < 0) {
@@ -411,14 +413,19 @@ int main(int argc, char **argv)
       }
 
       off_t len = lseek(fd, 0, SEEK_END);
-      const void *map = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
-      close(fd);
-      if (map == MAP_FAILED) {
-         fprintf(stderr, "Failed to mmap the file: errno=%d, %s\n",
-                 errno, strerror(errno));
+      size_t new_size = total_size + len;
+      all_inputs = reralloc_size(mem_ctx, all_inputs, new_size + 1);
+      if (!all_inputs) {
+         fprintf(stderr, "Failed to allocate memory\n");
          ralloc_free(mem_ctx);
          return 1;
       }
+      lseek(fd, 0, SEEK_SET);
+      read(fd, all_inputs + total_size, len);
+      close(fd);
+      total_size = new_size;
+      all_inputs[total_size] = '\0';
+   }
 
    const char *allowed_spirv_extensions[] = {
       "SPV_EXT_shader_atomic_float_add",
@@ -430,8 +437,8 @@ int main(int argc, char **argv)
 
    struct clc_compile_args clc_args = {
       .source = {
-            .name = *infile,
-            .value = map,
+         .name = "intel_clc_files",
+         .value = all_inputs,
       },
       .features = {
          .fp16 = true,
@@ -451,7 +458,6 @@ int main(int argc, char **argv)
       ralloc_free(mem_ctx);
       return 1;
    }
-   }
 
    util_dynarray_foreach(&spirv_objs, struct clc_binary, p) {
       util_dynarray_append(&spirv_ptr_objs, struct clc_binary *, p);