libsysprof-capture: Use assert() instead of g_assert()

Also use it instead of `g_return_if_fail()`.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #40

src/libsysprof-capture/sysprof-address.h

@@ -56,6 +56,7 @@
 
 #pragma once
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stdint.h>
 
@@ -65,7 +66,8 @@ G_BEGIN_DECLS
 
 typedef uint64_t SysprofAddress;
 
-G_STATIC_ASSERT (sizeof (SysprofAddress) >= sizeof (void *));
+static_assert (sizeof (SysprofAddress) >= sizeof (void *),
+               "Address space is too big");
 
 typedef enum
 {