Add missing patch

0001-preload-Better-debug-for-functions-missing-from-libc.patch

@@ -0,0 +1,44 @@
+From 6b4851b7dafc9015f673d59c692fadd7912e7ad2 Mon Sep 17 00:00:00 2001
+From: Bastien Nocera <hadess@hadess.net>
+Date: Thu, 22 Oct 2020 17:16:03 +0200
+Subject: [PATCH] preload: Better debug for functions missing from libc
+
+If finding one of the symbols for a function fails, whichever function
+it is, we'd get this error message:
+python3: src/libumockdev-preload.c:81: get_libc_func: Assertion `fp' failed.
+
+Update the code to throw an error on stderr before failing.
+---
+ src/libumockdev-preload.c | 10 +++++++---
+ 1 file changed, 7 insertions(+), 3 deletions(-)
+
+diff --git a/src/libumockdev-preload.c b/src/libumockdev-preload.c
+index 1011fac..9328dc1 100644
+--- a/src/libumockdev-preload.c
++++ b/src/libumockdev-preload.c
+@@ -78,15 +78,19 @@ get_libc_func(const char *f)
+ 	nextlib = dlopen("libc.so.6", RTLD_LAZY);
+ 
+     fp = dlsym(nextlib, f);
+-    assert(fp);
+ 
+     return fp;
+ }
+ 
+ #define libc_func(name, rettype, ...)			\
+     static rettype (*_ ## name) (__VA_ARGS__) = NULL;	\
+-    if (_ ## name == NULL)				\
+-        _ ## name = get_libc_func(#name);
++    if (_ ## name == NULL) {				\
++        _ ## name = get_libc_func(#name);		\
++        if (_ ## name == NULL) {			\
++            fprintf(stderr, "umockdev: could not get libc function "#name"\n"); \
++            abort();					\
++        }						\
++    }
+ 
+ /* return rdev of a file descriptor */
+ static dev_t
+-- 
+2.28.0
+