cmake: invoke the compiler to test arch features

We require SSSE3, and optionally support AVX2, and the best way of testing
the compiler and compile flags is to run the compiler.

CMakeLists.txt

@@ -237,6 +237,9 @@ if (RELEASE_BUILD)
     endif()
 endif()
 
+# ensure we are building for the right target arch
+include (${CMAKE_MODULE_PATH}/arch.cmake)
+
 # testing a builtin takes a little more work
 CHECK_C_SOURCE_COMPILES("void *aa_test(void *x) { return __builtin_assume_aligned(x, 16);}\nint main(void) { return 0; }" HAVE_CC_BUILTIN_ASSUME_ALIGNED)
 CHECK_CXX_SOURCE_COMPILES("void *aa_test(void *x) { return __builtin_assume_aligned(x, 16);}\nint main(void) { return 0; }" HAVE_CXX_BUILTIN_ASSUME_ALIGNED)
@@ -403,7 +406,6 @@ set (hs_exec_SRCS
     src/fdr/flood_runtime.h
     src/fdr/fdr_loadval.h
     src/fdr/teddy.c
-    src/fdr/teddy_avx2.c
     src/fdr/teddy.h
     src/fdr/teddy_internal.h
     src/fdr/teddy_runtime_common.h
@@ -513,7 +515,6 @@ set (hs_exec_SRCS
     src/util/fatbit.h
     src/util/fatbit.c
     src/util/join.h
-    src/util/masked_move.c
     src/util/masked_move.h
     src/util/multibit.h
     src/util/multibit_internal.h
@@ -540,6 +541,14 @@ set (hs_exec_SRCS
     src/database.h
 )
 
+if (HAVE_AVX2)
+    set (hs_exec_SRCS
+        ${hs_exec_SRCS}
+        src/fdr/teddy_avx2.c
+        src/util/masked_move.c
+        )
+endif ()
+
 
 SET (hs_SRCS
     ${hs_HEADERS}