build: remove bogous work-around for problems with sframes

This PR removes a work-around I thought would fix a problem with sframes
I ran into on my machine leading to linker errors while compiling ANTLR
(a dependency of substrait-cpp). Turns out that the root cause is that
CMake uses the system default compiler for dependencies fetched with
`FetchContent`, which is g++ on my machine (which emits sframes), which
may then linked with compilation units compiled by a different compiler,
which may break of LTO is enabled. The short-term solution is to set the
`CC?  and `CXX` environment variables to the same values as
`CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term
solution as substrait-io/substrait-cpp#145.

Signed-off-by: Ingo Müller <ingomueller@google.com>

Author: ingomueller-net

third_party/CMakeLists.txt

@@ -10,14 +10,6 @@ add_compile_options(
        $<$<CXX_COMPILER_ID:MSVC>:/FIcstdint>
        $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-include;cstdint>>")
 
-if(LLVM_ENABLE_LLD AND BUILD_SHARED_LIB)
-  # If system GAS generates .sframe sections (GAS >= 2.40 on ELF platforms) and
-  # building with `BUILD_SHARED_LIB`, we get lld linker errors in ANTLR during
-  # LTO, where static libs are linked into shared libs. Workaround: suppress
-  # .sframe generation in that situation.
-  set(ANTLR4_CPP_EXTRA_FLAGS "-Wa,--no-gsframe" CACHE INTERNAL "")
-endif()
-
 # The way how Substrait uses sanitizers seems to be incompatible with some flags
 # set by LLVM, leading to linker errors, so we deactivate them.
 set(SUBSTRAIT_CPP_SANITIZE_DEBUG_BUILD OFF)