Revert "[libc] New HeaderGen Switch Flip"

[RoseZhang03]

Reverts #99929

[llvmbot]

@llvm/pr-subscribers-libc

Author: None (RoseZhang03)

Changes

Reverts llvm/llvm-project#99929

---

Full diff: https://github.com/llvm/llvm-project/pull/100003.diff

1 Files Affected:

• (modified) libc/CMakeLists.txt (+1-1)

diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index 45cca17562d26..6e0760724d963 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -73,7 +73,7 @@ if(LIBC_BUILD_GPU_LOADER OR (LLVM_LIBC_GPU_BUILD AND NOT LLVM_RUNTIMES_BUILD))
   add_subdirectory(utils/gpu)
 endif()
 
-option(LIBC_USE_NEW_HEADER_GEN "Generate header files using new headergen instead of the old one" ON)
+option(LIBC_USE_NEW_HEADER_GEN "Generate header files using new headergen instead of the old one" OFF)
 
 set(NEED_LIBC_HDRGEN FALSE)
 if(NOT LLVM_RUNTIMES_BUILD)

[jhuber6]

Thanks, the minimum Python version accepted by LLVM is 3.8 and the minimum provided by Ubuntu LTS is 3.10, so see if you can get it to work with those.