<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/102879>102879</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang should use CFLAGS enviroment when set with --sysroot
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          xiedeacc
      </td>
    </tr>
</table>

<pre>
    when I use below command to build make, configure cannot find sys/types.h header file, that's because configure just pass --sysroot and -E to clang, so clang just try to find sys/types.h under sysroot, but search path was passed by CFLAGS to configure. I know configure should also pass CFLAGS, but current almost all project used configure program has same problem, so can clang inherit CFLAGS enviroment from configure?


```
AR=/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/bin/llvm-ar \
ARFLAGS= \
CC='/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/bin/clang --sysroot=/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/' \
CFLAGS='-U_FORTIFY_SOURCE -U_FORTIFY_SOURCE -fstack-protector -fno-omit-frame-pointer -Wall -v -nostdinc -g0 -O2 -D_FORTIFY_SOURCE=1 -DNDEBUG -ffunction-sections -fdata-sections -isystem /usr/include -isystem /usr/include/x86_64-linux-gnu -isystem /root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib/clang/18/include -no-canonical-prefixes -Wno-builtin-macro-redefined -D__DATE__=redacted -D__TIMESTAMP__=redacted -D__TIME__=redacted -g' \
LD='/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/bin/clang --sysroot=/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/' \
LDFLAGS='-Wl,-S -v -B/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/bin -L/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib -Wl,--build-id=md5 -Wl,--hash-style=gnu -Wl,-z,relro,-z,now -Wl,-no-as-needed -lstdc++ -lc -lm -fuse-ld=lld -rtlib=compiler-rt -B/usr/lib/x86_64-linux-gnu -L/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib -Wl,-rpath,/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib -L/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib/x86_64-unknown-linux-gnu -Wl,-rpath,/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib/x86_64-unknown-linux-gnu -L/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib/clang/18/lib/x86_64-unknown-linux-gnu -Wl,-rpath,/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/external/cc_toolchain_repo_amd64_x86_64_clang/lib/clang/18/lib/x86_64-unknown-linux-gnu -L/usr/lib/x86_64-linux-gnu -Wl,-rpath,/usr/lib/x86_64-linux-gnu -Wl,--gc-sections' \
./configure --without-guile --with-guile=no --disable-dependency-tracking --prefix=/root/.cache/bazel/_bazel_root/d7f4cad81e2b036f4c3382027c9d9c7a/sandbox/sandbox_stash/BootstrapGNUMake/43215/execroot/bazel_template/bazel-out/k8-opt-exec-ST-47bf8d7f3fd8/bin/external/rules_foreign_cc/toolchains/private/make.build_tmpdir --verbose
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsV91u27gSfhr6hhhDpuxYvvBFYkVFgLQ9aBIU50qgyJHFhiIFkkriPv0BJTlx2p7dLrBAssAChiX-zQy_mdHMx71Xe4O4JasLsspnvA-NddsnhRK5ELPKysP2sUFDr2jvkVao7SMVtm25kTRYWvVKS9ryeyRsR4U1tdr3DqngxthAa2Uk9QdPWBEOHfp5QxvkEh2tlR6OhIYHwtaeVih4VPEi41vvA-249xTAH7yzNtCoFi6jZqG52UcJfnof9wd3iKu_UNybqHcSFA9WfaAeuRMN7Xho6CP3gzqUtDrQXXF9_uFm0HS0aE6v6L0ZADja6Bvba0m59nY0dTx2FC9659AEynVrfXxo2jn7DUWIcMoTQZ2ze8db2nBPPW-HiUpje7whN9MtlWnQqXC0D82DcraNSmpn2xeJJC1IkpPk_NX_WTL9huH5F5LmhBUjIsVccNEgYUXFv6MmrCiHl3Jalut6KbjMFsiqJD2rlyJNM5awtdjIjVhzwgp8CugMj2eFKIO1WjRcmdJhZ0veyrNl-ZSdlWfLcnJfUSlDWKH1QwvcUbLaHS0bcUzzl7ndbrB2_R4MHn3xHJdvDiNh6xOgjtgRtoa7svj85faq-G958_nuy-6S_mKm9oGLe-icDSiCdRRqY8G2KkDteIvQWWUCOgpfYwjDAwVjfZDKCAr7hMJnRiH_QSxJ8wWF_FN-eXH3gUJd90YEZQ14HJ6eQi154Cdj5Q8-YEsJK3rvCCuUEbqX-P9XCCtGJEAr0z_B3vSvNr-hS7SqjoFCWLHITq9jLAhurFGCa-gc1uoJPYWvxkL8ogZloOXCWXAosVYGZcS3zM9vL8uSpLlDyUWYZm-vPl7e3J5__M-vl36Y3b8Klev835z6rZy6zk-T6qsmbAc3QyZcvDl2FK7fPNTphMkQvxKUJGneytXzdMN9Az4cNJI0H7J0XPhO2M6hdvY4iPV1WjMWuAeDKGPgah-kIOyCsAsKWlDQLYW69wg6KtNaUnAhZl2aC9t2SqMDF0YHjR-NMSV__mC8H_hc7EQI270Dg94elBdf9Sb2XebUZ-8Mrz-09V1A-aoS_fPQ_UvmX_9pyv90wd_ZDnvx3K28qg7zaOBzLw_wqEJj-wD7XunjeByQNDeWAkjleaURJHZoJBpxgOC4uFdDCRxbgr-5AnpuZGWfXt5KH7hvCCsurA0-ON59-HT3ceByxTJli9XgLhSTilFfwLbTPDxbAraPi_cZ2C5A3A43t7BcV3Um13Vay-y5wJ-43vUafVlbh2pvSiEiTzuGQiRtnVMPo5LILedDUSlD20nlKMADusp6_IHTzOQ2lZt0w2e4XaxZulxtzlg2a7aLWogFX63SVc2rbLVZ4qpartJqJapEJNl6prYsYcskW7BFslwn2Xy54bziG0xllqIUSJYJtlzpeSQqc-v2M-V9j9tFwrL1ZqZ5hdoPJJqxKVBZ5NNuOzCbqt97sky08sG_iAgqaNyOXc_EIyMB_pnYDQTcY6AxjF4apFnv9LYJofMkPR_6lWKvQtNXc2HbiVQdudXEOmMPGg2PEE-2P2zZ_wIAAP__izM2_A">