BUILD: ssl: fix shctx build on RHEL with futex
On RHEL/CentOS, linux/futex.h uses an u32 type which is never declared
anywhere. Let's set it with a #define in order to fix the issue without
causing conflicts with possible typedefs on other platforms.
diff --git a/src/shctx.c b/src/shctx.c
index 5fe2e7e..c6c6737 100644
--- a/src/shctx.c
+++ b/src/shctx.c
@@ -14,6 +14,9 @@
#include <sys/mman.h>
#ifdef USE_SYSCALL_FUTEX
#include <unistd.h>
+#ifndef u32
+#define u32 unsigned int
+#endif
#include <linux/futex.h>
#include <sys/syscall.h>
#else /* USE_SYSCALL_FUTEX */