Implement default VMM directory

src/config.c

@@ -143,8 +143,7 @@ load_global(void)
     if (p != NULL)
         strncpy(vmm_path, p, sizeof(vmm_path) - 1);
     else
-        // [todo] plat_vmm_path()
-        vmm_path[0] = 0;
+        plat_get_vmm_dir(vmm_path, sizeof(vmm_path));
 }
 
 /* Load "General" section. */
@@ -2215,7 +2214,10 @@ save_global(void)
     else
         ini_section_delete_var(cat, "vmm_disabled");
 
-    ini_section_set_string(cat, "vmm_path", vmm_path);
+    if (vmm_path[0] != 0)
+        ini_section_set_string(cat, "vmm_path", vmm_path);
+    else
+        ini_section_delete_var(cat, "vmm_path");
 }
 
 /* Save "General" section. */

src/include/86box/plat.h

@@ -146,6 +146,7 @@ extern void     plat_get_exe_name(char *s, int size);
 extern void     plat_get_global_config_dir(char *outbuf, size_t len);
 extern void     plat_get_global_data_dir(char *outbuf, size_t len);
 extern void     plat_get_temp_dir(char *outbuf, uint8_t len);
+extern void     plat_get_vmm_dir(char *outbuf, uint8_t len);
 extern void     plat_init_rom_paths(void);
 extern int      plat_dir_check(char *path);
 extern int      plat_dir_create(char *path);

src/qt/qt_platform.cpp

@@ -694,6 +694,20 @@ plat_get_temp_dir(char *outbuf, const uint8_t len)
     strncpy(outbuf, dir.canonicalPath().toUtf8().constData(), len);
 }
 
+void
+plat_get_vmm_dir(char *outbuf, const size_t len)
+{
+    const auto dir = QDir(QStandardPaths::standardLocations(QStandardPaths::HomeLocation)[0]).filePath("86Box VMs");
+
+    if (!dir.exists()) {
+        if (!dir.mkpath(".")) {
+            qWarning("Failed to create VMs directory %s", dir.absolutePath().toUtf8().constData());
+        }
+    }
+
+    strncpy(outbuf, dir.canonicalPath().toUtf8().constData(), len);
+}
+
 void
 plat_init_rom_paths(void)
 {

src/unix/unix.c

@@ -901,6 +901,14 @@ plat_get_temp_dir(char *outbuf, uint8_t len)
     path_slash(outbuf);
 }
 
+void
+plat_get_vmm_dir(char *outbuf, const size_t len)
+{
+    // Return empty string. SDL 86Box does not have a VM manager
+    if (len > 0)
+        outbuf[0] = 0;
+}
+
 bool
 process_media_commands_3(uint8_t *id, char *fn, uint8_t *wp, int cmdargc)
 {