diff --git a/libc/cmake/modules/LLVMLibCObjectRules.cmake b/libc/cmake/modules/LLVMLibCObjectRules.cmake
--- a/libc/cmake/modules/LLVMLibCObjectRules.cmake
+++ b/libc/cmake/modules/LLVMLibCObjectRules.cmake
@@ -21,7 +21,12 @@
   set(compile_options ${LIBC_COMPILE_OPTIONS_DEFAULT} ${ARGN})
   if(LLVM_COMPILER_IS_GCC_COMPATIBLE)
     list(APPEND compile_options "-fpie")
-    list(APPEND compile_options "-ffreestanding")
+
+    if(LLVM_LIBC_FULL_BUILD)
+      # Only add -ffreestanding flag in full build mode.
+      list(APPEND compile_options "-ffreestanding")
+    endif()
+
     list(APPEND compile_options "-fno-builtin")
     list(APPEND compile_options "-fno-exceptions")
     list(APPEND compile_options "-fno-lax-vector-conversions")
diff --git a/libc/cmake/modules/LLVMLibCTestRules.cmake b/libc/cmake/modules/LLVMLibCTestRules.cmake
--- a/libc/cmake/modules/LLVMLibCTestRules.cmake
+++ b/libc/cmake/modules/LLVMLibCTestRules.cmake
@@ -156,8 +156,14 @@
   )
   target_compile_options(
     ${fq_build_target_name}
-    PRIVATE -fpie -ffreestanding ${LIBC_COMPILE_OPTIONS_DEFAULT}
+    PRIVATE -fpie ${LIBC_COMPILE_OPTIONS_DEFAULT}
   )
+  if(LLVM_LIBC_FULL_BUILD)
+    target_compile_options(
+      ${fq_build_target_name}
+      PRIVATE -ffreestanding
+    )
+  endif()
   if(LIBC_UNITTEST_COMPILE_OPTIONS)
     target_compile_options(
       ${fq_build_target_name}