This patch changes libkmod so it honors the 'LINUX_MODULE_DIRECTORY'
environment variable, rather than looking for modules exclusively in
/lib/modules.

Patch by Shea Levy and Eelco Dolstra, from Nixpkgs; adjusted to
use 'LINUX_MODULE_DIRECTORY' rather than 'MODULE_DIR' as the variable
name.


--- kmod-7/libkmod/libkmod.c	2012-03-15 08:19:16.750010226 -0400
+++ kmod-7/libkmod/libkmod.c	2012-04-04 15:21:29.532074313 -0400
@@ -200,7 +200,7 @@
 static char *get_kernel_release(const char *dirname)
 {
 	struct utsname u;
-	char *p;
+	char *p, *dirname_prefix;
 
 	if (dirname != NULL)
 		return path_make_absolute_cwd(dirname);
@@ -208,7 +208,10 @@
 	if (uname(&u) < 0)
 		return NULL;
 
-	if (asprintf(&p, "%s/%s", dirname_default_prefix, u.release) < 0)
+	if ((dirname_prefix = getenv("LINUX_MODULE_DIRECTORY")) == NULL)
+		dirname_prefix = dirname_default_prefix;
+
+	if (asprintf(&p, "%s/%s", dirname_prefix, u.release) < 0)
 		return NULL;
 
 	return p;

--- kmod-17/tools/static-nodes.c	2013-12-17 22:05:42.159047316 +0100
+++ kmod-17/tools/static-nodes.c	2014-04-17 13:51:17.945974320 +0200
@@ -159,6 +159,7 @@
 	FILE *in = NULL, *out = NULL;
 	const struct static_nodes_format *format = &static_nodes_format_human;
 	int r, ret = EXIT_SUCCESS;
+	char *dirname_prefix;
 
 	for (;;) {
 		int c, idx = 0, valid;
@@ -211,16 +212,19 @@
 		goto finish;
 	}
 
-	snprintf(modules, sizeof(modules), "/lib/modules/%s/modules.devname", kernel.release);
+	if ((dirname_prefix = getenv("LINUX_MODULE_DIRECTORY")) == NULL)
+		dirname_prefix = "/lib/modules";
+
+	snprintf(modules, sizeof(modules), "%s/%s/modules.devname", dirname_prefix, kernel.release);
 	in = fopen(modules, "re");
 	if (in == NULL) {
 		if (errno == ENOENT) {
-			fprintf(stderr, "Warning: /lib/modules/%s/modules.devname not found - ignoring\n",
-				kernel.release);
+			fprintf(stderr, "Warning: %s/%s/modules.devname not found - ignoring\n",
+				dirname_prefix, kernel.release);
 			ret = EXIT_SUCCESS;
 		} else {
-			fprintf(stderr, "Error: could not open /lib/modules/%s/modules.devname - %m\n",
-				kernel.release);
+			fprintf(stderr, "Error: could not open %s/%s/modules.devname - %m\n",
+				dirname_prefix, kernel.release);
 			ret = EXIT_FAILURE;
 		}
 		goto finish;
nt'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/cpio.scm?id=4f6172f1c5c603cd58f85821bf7a80e716b0c67e&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2016-04-03 14:19:09 +0200'>2016-04-03</span></td><td><a href='/guix/commit/tests/cpio.scm?id=a9edb211e733b8b34e67ec3b4450567e9376986f'>build: Add a Guile custom test driver using SRFI-64.</a><span class='msg-avail'>...</span></td><td>Mathieu Lirzin</td></tr>