universe: Update the default GCC toolchain to GCC 14

Reviewed by:	imp, emaste
Differential Revision:	https://reviews.freebsd.org/D49160

Author: bsdjhb

Makefile

@@ -540,7 +540,7 @@ TARGET_ARCHES_${target}= ${MACHINE_ARCH_LIST_${target}}
 .endfor
 
 .if defined(USE_GCC_TOOLCHAINS)
-_DEFAULT_GCC_VERSION=	gcc12
+_DEFAULT_GCC_VERSION=	gcc14
 _GCC_VERSION=		${"${USE_GCC_TOOLCHAINS:Mgcc*}" != "":?${USE_GCC_TOOLCHAINS}:${_DEFAULT_GCC_VERSION}}
 TOOLCHAINS_amd64=	amd64-${_GCC_VERSION}
 TOOLCHAINS_arm=		armv7-${_GCC_VERSION}