clamav: Fix compiling

glibc headers were not correctly included

src/patches/clamav/llvm-glibc.patch

@@ -0,0 +1,12 @@
+Index: clamav-0.97.3/libclamav/c++/llvm/lib/ExecutionEngine/JIT/Intercept.cpp
+===================================================================
+--- clamav-0.97.3.orig/libclamav/c++/llvm/lib/ExecutionEngine/JIT/Intercept.cpp
++++ clamav-0.97.3/libclamav/c++/llvm/lib/ExecutionEngine/JIT/Intercept.cpp
+@@ -52,6 +52,7 @@ static void runAtExitHandlers() {
+ #include <sys/stat.h>
+ #endif
+ #include <fcntl.h>
++#include <unistd.h>
+ /* stat functions are redirecting to __xstat with a version number.  On x86-64 
+  * linking with libc_nonshared.a and -Wl,--export-dynamic doesn't make 'stat' 
+  * available as an exported symbol, so we have to add it explicitly.