wpa_supplicant: use unique IDs for networks and credentials

Fixes the bug described at https://github.com/NixOS/nixpkgs/pull/155266#issuecomment-1031711094

pkgs/os-specific/linux/wpa_supplicant/Use-unique-IDs-for-networks-and-credentials.patch

@@ -0,0 +1,32 @@
+The id and cred_id variables are reset to 0 every time the
+wpa_config_read function is called, which is fine as long as it is only
+called once. However, this is not the case when using both the -c and -I
+options to specify two config files.
+
+This is a problem because the GUI, since eadfeb0e93748eb396ae62012b92d21a7f533646,
+relies on the network IDs being unique (and increasing), and might get
+into an infinite loop otherwise.
+
+This is solved by simply making the variables static.
+---
+ wpa_supplicant/config_file.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/wpa_supplicant/config_file.c b/wpa_supplicant/config_file.c
+index 6db5010db..c996e3916 100644
+--- a/wpa_supplicant/config_file.c
++++ b/wpa_supplicant/config_file.c
+@@ -297,8 +297,8 @@ struct wpa_config * wpa_config_read(const char *name, struct wpa_config *cfgp)
+ 	struct wpa_ssid *ssid, *tail, *head;
+ 	struct wpa_cred *cred, *cred_tail, *cred_head;
+ 	struct wpa_config *config;
+-	int id = 0;
+-	int cred_id = 0;
++	static int id = 0;
++	static int cred_id = 0;
+
+ 	if (name == NULL)
+ 		return NULL;
+--
+2.34.1
+

pkgs/os-specific/linux/wpa_supplicant/default.nix

@@ -18,6 +18,8 @@ stdenv.mkDerivation rec {
   };
 
   patches = [
+    # Fix a bug when using two config files
+    ./Use-unique-IDs-for-networks-and-credentials.patch
   ] ++ lib.optionals readOnlyModeSSIDs [
     # Allow read-only networks
     ./0001-Implement-read-only-mode-for-ssids.patch