build: Enable -Wcast-align=strict warning

Author: real-or-random

configure.ac

@@ -99,6 +99,7 @@ AC_DEFUN([SECP_TRY_APPEND_DEFAULT_CFLAGS], [
     SECP_TRY_APPEND_CFLAGS([-Wno-unused-function], $1) # GCC >= 3.0, -Wunused-function is implied by -Wall.
     SECP_TRY_APPEND_CFLAGS([-Wextra], $1) # GCC >= 3.4, this is the newer name of -W, which we don't use because older GCCs will warn about unused functions.
     SECP_TRY_APPEND_CFLAGS([-Wcast-align], $1) # GCC >= 2.95
+    SECP_TRY_APPEND_CFLAGS([-Wcast-align=strict], $1) # GCC >= 8.0
     SECP_TRY_APPEND_CFLAGS([-Wconditional-uninitialized], $1) # Clang >= 3.0 only
     SECP_TRY_APPEND_CFLAGS([-fvisibility=hidden], $1) # GCC >= 4.0