fix: switch back to gcc

Dockerfile.openj9

@@ -5,10 +5,10 @@ FROM ubuntu:25.04 AS build
 RUN apt -qq update \
   && apt -qq upgrade -y \
   && apt -qq install -y --no-install-recommends \
-    ant ant-contrib autoconf build-essential ca-certificates clang cmake cpio curl execstack file git \
+    ant ant-contrib autoconf build-essential ca-certificates cmake cpio curl execstack file gcc g++ git \
     libasound2-dev libcups2-dev libdwarf-dev libelf-dev libexpat1-dev libffi-dev libfontconfig libfontconfig1-dev \
     libfreetype6-dev libnuma-dev libssl-dev libx11-dev libxext-dev libxrandr-dev libxrender-dev libxt-dev libxtst-dev \
-    llvm-dev lld make nasm pkg-config python3 python3-dev rsync systemtap-sdt-dev unzip wget xvfb zip zlib1g-dev unzip \
+    make nasm pkg-config python3 python3-dev rsync systemtap-sdt-dev unzip wget xvfb zip zlib1g-dev unzip \
   && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /build
@@ -27,18 +27,13 @@ RUN git clone --single-branch --depth 1 \
 WORKDIR /build/src
 RUN bash get_source.sh
 
-ENV CC=/usr/bin/clang CXX=/usr/bin/clang++ LD=/usr/bin/lld
+ENV CC=/usr/bin/gcc CXX=/usr/bin/g++
   # TODO: add as args to configure
   # CFLAGS="-O3 -flto -fwhole-program-vtables" \
   # LDFLAGS="-Wl,-O1"
-ENV CFLAGS="-Wno-error=nontrivial-memcall"
 RUN bash configure \
   --with-boot-jdk=/build/bootjdk \
-  --with-openssl=system \
-  --with-toolchain-type=clang \
-  --enable-jvm-feature-link-time-opt \
-  --with-extra-cflags="$CFLAGS" \
-  --with-extra-cxxflags="$CFLAGS"
+  --with-openssl=system
 RUN make all JOBS=$(nproc)
 
 # jlink by advice from https://adoptium.net/blog/2021/10/jlink-to-produce-own-runtime/