Revert sys/ucontext.h change

Author: filipnavara

src/coreclr/nativeaot/Runtime/unix/UnixContext.h

@@ -4,7 +4,7 @@
 #ifndef __UNIX_CONTEXT_H__
 #define __UNIX_CONTEXT_H__
 
-#include <sys/ucontext.h>
+#include <ucontext.h>
 
 // Convert Unix native context to PAL_LIMITED_CONTEXT
 void NativeContextToPalContext(const void* context, PAL_LIMITED_CONTEXT* palContext);

src/coreclr/pal/src/configure.cmake

@@ -615,7 +615,7 @@ endif()
 
 check_c_source_compiles("
 #include <libunwind.h>
-#include <sys/ucontext.h>
+#include <ucontext.h>
 int main(int argc, char **argv)
 {
         unw_context_t libUnwindContext;

src/coreclr/pal/src/include/pal/context.h

@@ -33,7 +33,7 @@ extern "C"
 /* A type to wrap the native context type, which is ucontext_t on some
  * platforms and another type elsewhere. */
 #if HAVE_UCONTEXT_T
-#include <sys/ucontext.h>
+#include <ucontext.h>
 
 typedef ucontext_t native_context_t;
 #else   // HAVE_UCONTEXT_T