Update GCC version

Author: mintsuki

.github/workflows/nightly.yml

@@ -24,9 +24,9 @@ jobs:
         run: |
           set -ex
 
-          GCC_VERSION=14.2.0
+          GCC_VERSION=15.2.0
 
-          for i in aarch64 loongarch64 riscv64; do
+          for i in aarch64 loongarch64 riscv64 x86_64 i386; do
               wget https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/$GCC_VERSION/x86_64-gcc-$GCC_VERSION-nolibc-$i-linux.tar.gz
               tar -xf x86_64-gcc-$GCC_VERSION-nolibc-$i-linux.tar.gz
               export PATH="$(pwd -P)"/gcc-$GCC_VERSION-nolibc/$i-linux/bin:"$PATH"
@@ -38,6 +38,8 @@ jobs:
 
           export PACKAGES_PATH="$(pwd -P)"/edk2
 
+          export GCC5_IA32_PREFIX=i386-linux-
+          export GCC5_X64_PREFIX=x86_64-linux-
           export GCC5_AARCH64_PREFIX=aarch64-linux-
           export GCC5_LOONGARCH64_PREFIX=loongarch64-linux-
           export GCC5_RISCV64_PREFIX=riscv64-linux-