[libc][complex] Silence pedantic warning (llvm#112239)

Fix buildbot errors due to llvm#111659

Author: Sh0g0-1758

libc/cmake/modules/LLVMLibCCompileOptionRules.cmake

@@ -154,6 +154,7 @@ function(_get_common_compile_options output_var flags)
     list(APPEND compile_options "-Wno-sign-conversion")
     # Silence this warning because _Complex is a part of C99.
     list(APPEND compile_options "-Wno-c99-extensions")
+    list(APPEND compile_options "-Wno-pedantic")
     list(APPEND compile_options "-Wimplicit-fallthrough")
     list(APPEND compile_options "-Wwrite-strings")
     list(APPEND compile_options "-Wextra-semi")
@@ -231,6 +232,7 @@ function(_get_common_test_compile_options output_var c_test flags)
     # list(APPEND compile_options "-Wextra-semi")
     # Silence this warning because _Complex is a part of C99.
     list(APPEND compile_options "-Wno-c99-extensions")
+    list(APPEND compile_options "-Wno-pedantic")
     # if(NOT CMAKE_COMPILER_IS_GNUCXX)
     #   list(APPEND compile_options "-Wnewline-eof")
     #   list(APPEND compile_options "-Wnonportable-system-include-path")