Enable builds with GCC (#527)

* Enable builds with GCC

* Update travis.sh

.remill_commit_id

@@ -1 +1 @@
-084fe9f39059490657a065b20ec890bb25fd092a
+20bfadd947c74cad53c17061eddf055565e46463

cmake/settings.cmake

@@ -1,6 +1,3 @@
-# This is an exact copy of the cmake/settings.cmake file in the Remill
-# repository; you are encouraged to keep them in sync
-
 # This is only executed once; use a macro (and not a function) so that
 # everything defined here does not end up in a separate namespace
 macro(main)
@@ -88,15 +85,21 @@ macro(main)
     set(GLOBAL_CXXFLAGS
       -Wall -Wextra -Wno-unused-parameter -Wno-c++98-compat
       -Wno-unreachable-code-return -Wno-nested-anon-types
-      -Wno-extended-offsetof -Wgnu-alignof-expression
-      -Wno-gnu-anonymous-struct -Wno-gnu-designator
-      -Wno-variadic-macros -Wno-gnu-zero-variadic-macro-arguments
-      -Wno-gnu-statement-expression -Wno-return-type-c-linkage
+      -Wno-extended-offsetof
+      -Wno-variadic-macros -Wno-return-type-c-linkage
       -Wno-c99-extensions -Wno-ignored-attributes -Wno-unused-local-typedef
       -Wno-unknown-pragmas -Wno-unknown-warning-option -fPIC
       -fno-omit-frame-pointer -fvisibility-inlines-hidden -fno-exceptions
-      -fno-asynchronous-unwind-tables -fno-rtti
+      -fno-asynchronous-unwind-tables
     )
+    
+    if ("${CMAKE_C_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_C_COMPILER_ID}" STREQUAL "AppleClang")
+      set(GLOBAL_CXXFLAGS
+        ${GLOBAL_CXXFLAGS}
+        -Wgnu-alignof-expression -Wno-gnu-anonymous-struct -Wno-gnu-designator
+        -Wno-gnu-zero-variadic-macro-arguments -Wno-gnu-statement-expression
+      )
+    endif()
 
     # debug symbols
     if(CMAKE_BUILD_TYPE STREQUAL "Debug" OR CMAKE_BUILD_TYPE STREQUAL "RelWithDebInfo")

cmake/utils.cmake

@@ -8,6 +8,7 @@ function(FindAndSelectClangCompiler)
   if(DEFINED LLVM_INSTALL_PREFIX)
     list(APPEND FINDPACKAGE_LLVM_HINTS "${LLVM_INSTALL_PREFIX}/lib/cmake/llvm/")
     list(APPEND FINDPACKAGE_LLVM_HINTS "${LLVM_INSTALL_PREFIX}/share/llvm/cmake/")
+    set(FINDPACKAGE_LLVM_HINTS ${FINDPACKAGE_LLVM_HINTS} PARENT_SCOPE)
 
     message(STATUS "Using LLVM_INSTALL_PREFIX hints for find_package(LLVM): ${FINDPACKAGE_LLVM_HINTS}")
   endif()
@@ -28,10 +29,6 @@ function(FindAndSelectClangCompiler)
       set(CMAKE_C_COMPILER "clang" PARENT_SCOPE)
     endif()
   endif()
-  
-  if (NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "Clang" AND NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "AppleClang")
-    message(FATAL_ERROR "Remill and its dependent libraries must be compiled with Clang.")
-  endif()
 
   if(NOT DEFINED CMAKE_CXX_COMPILER)
     if(DEFINED LLVM_INSTALL_PREFIX)
@@ -41,10 +38,6 @@ function(FindAndSelectClangCompiler)
       set(CMAKE_CXX_COMPILER "clang++${executable_extension}" PARENT_SCOPE)
     endif()
   endif()
-  
-  if (NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
-    message(FATAL_ERROR "Remill and its dependent libraries must be compiled with Clang.")
-  endif()
 
   if(NOT DEFINED CMAKE_ASM_COMPILER)
     if(DEFINED LLVM_INSTALL_PREFIX)

scripts/travis.sh

@@ -162,8 +162,8 @@ linux_build() {
   local log_file=`mktemp`
 
   # set up ada support for cmake
-  # Old supported versions: "35" "36" "37" "38" "39" 
-  llvm_version_list=( "40" "50" "60" )
+  # Old supported versions: "35" "36" "37" "38" "39" "40" 
+  llvm_version_list=( "50" "60" )
   for llvm_version in "${llvm_version_list[@]}" ; do
     printf "#\n"
     printf "# Running CI tests for LLVM version ${llvm_version}...\n"