Enable portable home/config dirs for extract-and-run (AppImage#5)

* Enable portable home/config dirs for extract-and-run

* Make the build work with Alpine 3.17

---------

Co-authored-by: probonopd <[email protected]>

Author: xordspar0

src/runtime/runtime.c

@@ -1434,6 +1434,27 @@ char* appimage_hexlify(const char* bytes, const size_t numBytes) {
     return hexlified;
 }
 
+void set_portable_home_and_config(char* basepath) {
+    char portable_home_dir[PATH_MAX];
+    char portable_config_dir[PATH_MAX];
+
+    /* If there is a directory with the same name as the AppImage plus ".home", then export $HOME */
+    strcpy(portable_home_dir, basepath);
+    strcat(portable_home_dir, ".home");
+    if (is_writable_directory(portable_home_dir)) {
+        fprintf(stderr, "Setting $HOME to %s\n", portable_home_dir);
+        setenv("HOME", portable_home_dir, 1);
+    }
+
+    /* If there is a directory with the same name as the AppImage plus ".config", then export $XDG_CONFIG_HOME */
+    strcpy(portable_config_dir, basepath);
+    strcat(portable_config_dir, ".config");
+    if (is_writable_directory(portable_config_dir)) {
+        fprintf(stderr, "Setting $XDG_CONFIG_HOME to %s\n", portable_config_dir);
+        setenv("XDG_CONFIG_HOME", portable_config_dir, 1);
+    }
+}
+
 int main(int argc, char* argv[]) {
     const bool verbose = (getenv("VERBOSE") != NULL);
     if (verbose) {
@@ -1614,6 +1635,8 @@ int main(int argc, char* argv[]) {
             setenv("ARGV0", argv0_path, 1);
             setenv("APPDIR", prefix, 1);
 
+            set_portable_home_and_config(fullpath);
+
             execv(apprun_path, new_argv);
 
             int error = errno;
@@ -1803,24 +1826,7 @@ int main(int argc, char* argv[]) {
         setenv("ARGV0", argv0_path, 1);
         setenv("APPDIR", mount_dir, 1);
 
-        char portable_home_dir[PATH_MAX];
-        char portable_config_dir[PATH_MAX];
-
-        /* If there is a directory with the same name as the AppImage plus ".home", then export $HOME */
-        strcpy(portable_home_dir, fullpath);
-        strcat(portable_home_dir, ".home");
-        if (is_writable_directory(portable_home_dir)) {
-            fprintf(stderr, "Setting $HOME to %s\n", portable_home_dir);
-            setenv("HOME", portable_home_dir, 1);
-        }
-
-        /* If there is a directory with the same name as the AppImage plus ".config", then export $XDG_CONFIG_HOME */
-        strcpy(portable_config_dir, fullpath);
-        strcat(portable_config_dir, ".config");
-        if (is_writable_directory(portable_config_dir)) {
-            fprintf(stderr, "Setting $XDG_CONFIG_HOME to %s\n", portable_config_dir);
-            setenv("XDG_CONFIG_HOME", portable_config_dir, 1);
-        }
+        set_portable_home_and_config(fullpath);
 
         /* Original working directory */
         char cwd[1024];