Fixup [TO SQUASH]

1. https://cmake.org/cmake/help/latest/variable/CMAKE_SIZEOF_VOID_P.html

cmake/SetClangRTLibDir.cmake

@@ -1,14 +1,25 @@
 # The function sets the given variable in a parent scope to a
-# value in CLANG_RT_LIB_DIR environment variable if it
+# value in FUZZER_NO_MAIN_LIBRARY environment variable if it
 # is set. Otherwise the value with path to a directory with
-# Clang RT libraries is composed manually. Function raises
-# a fatal message if C compiler is not Clang.
+# libclang_rt.fuzzer_no_main library is composed manually.
+# Function raises a fatal message if C compiler is not Clang.
+#
+# On Linux installations libFuzzer library is typically located at:
+#
+# /usr/lib/<llvm-version>/lib/clang/<clang-version>/lib/linux/libclang_rt.fuzzer_no_main-<architecture>.a
+#
+# Location is LLVM_LIBRARY_DIRS/clang/<version>/lib/<OS>/,
+# for example LLVM_LIBRARY_DIRS/clang/4.0.0/lib/darwin/.
+#
+# 1. https://llvm.org/docs/LibFuzzer.html#using-libfuzzer-as-a-library
 
-function(SetClangRTLibDir outvar)
-  set(ClangRTLibDir $ENV{CLANG_RT_LIB_DIR})
+function(SetFuzzerNoMainLibPath outvar)
   if (NOT CMAKE_C_COMPILER_ID STREQUAL "Clang")
     message(FATAL_ERROR "C compiler is not a Clang")
   endif ()
+
+  set(ClangRTLibDir $ENV{FUZZER_NO_MAIN_LIBRARY})
+
   if (NOT ClangRTLibDir)
     string(REPLACE "." ";" VERSION_LIST ${CMAKE_C_COMPILER_VERSION})
     list(GET VERSION_LIST 0 CLANG_VERSION_MAJOR)
@@ -18,7 +29,20 @@ function(SetClangRTLibDir outvar)
     if (CLANG_VERSION_MAJOR GREATER 15)
       set(CLANG_VERSION ${CLANG_VERSION_MAJOR})
     endif ()
-    set(ClangRTLibDir "/usr/lib/llvm-${CLANG_VERSION_MAJOR}/lib/clang/${CLANG_VERSION}/lib/linux/")
+
+    if (CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(ARCH "i386")
+    elseif (CMAKE_SIZEOF_VOID_P EQUAL 8)
+      set(ARCH "x86_64")
+    endif ()
+
+    # find_package(LLVM 17 REQUIRED CONFIG)
+    # FIXME: Check presence of LLVM.
+    # set(LLVM_BASE "${LLVM_LIBRARY_DIRS}/clang/")
+
+    string(TOLOWER ${CMAKE_HOST_SYSTEM_NAME} OS_NAME)
+
+    set(ClangRTLibDir "/usr/lib/clang/${CLANG_VERSION}/lib/${OS_NAME}/libclang_rt.fuzzer_no_main-${ARCH}.a")
   endif ()
   set(${outvar} ${ClangRTLibDir} PARENT_SCOPE)
   message(STATUS "[SetClangRTLibDir] ${outvar} is ${ClangRTLibDir}")

luzer/CMakeLists.txt

@@ -1,4 +1,4 @@
-SetClangRTLibDir(ClangRTLibraryDir)
+SetFuzzerNoMainLibPath(FUZZER_NO_MAIN_LIBRARY)
 
 configure_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/version.c
@@ -16,12 +16,10 @@ add_library(${CMAKE_PROJECT_NAME} SHARED ${LUZER_SOURCES})
 target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE
 	${LUA_INCLUDE_DIR}
 )
-target_link_directories(${CMAKE_PROJECT_NAME} PRIVATE
-                        ${ClangRTLibraryDir})
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE
 	${LUA_LIBRARIES}
 	-fsanitize=fuzzer-no-link
-	clang_rt.fuzzer_no_main-x86_64
+	${FUZZER_NO_MAIN_LIBRARY}
 )
 target_compile_options(${CMAKE_PROJECT_NAME} PRIVATE
 	-D_FORTIFY_SOURCE=2