diff --git a/examples/main.c b/examples/main.c
index cdec187d69d60cdd363c2146317f2dc00ef09e2e..9715aa665fd053578f0f98d53bf15d5ef2af9706 100644
--- a/examples/main.c
+++ b/examples/main.c
@@ -391,7 +391,7 @@ int main(int argc, char *argv[]) {
   }
 
 /* Do we have slow barriers? */
-#ifdef HAVE_PTHREAD_BARRIERS
+#ifndef HAVE_PTHREAD_BARRIERS
   if (myrank == 0)
     message(
         "WARNING: Slow homemade thread barriers in use. Code will be slower.");
diff --git a/m4/ax_cc_maxopt.m4 b/m4/ax_cc_maxopt.m4
index 2f1e9a2fdfb9f63a1108cef41bd1373911ad8345..0fcef66c7542fbb840e68d259550343a1a5601a1 100644
--- a/m4/ax_cc_maxopt.m4
+++ b/m4/ax_cc_maxopt.m4
@@ -171,7 +171,7 @@ if test "$ac_test_CFLAGS" != "set"; then
 
      #  -fstrict-aliasing for gcc-2.95+
      AX_CHECK_COMPILE_FLAG(-fstrict-aliasing,
-       CFLAGS="$CFLAGS -fstrict-aliasing")
+        CFLAGS="$CFLAGS -fstrict-aliasing")
 
      # note that we enable "unsafe" fp optimization with other compilers, too
      AX_CHECK_COMPILE_FLAG(-ffast-math, CFLAGS="$CFLAGS -ffast-math")
diff --git a/m4/ax_gcc_archflag.m4 b/m4/ax_gcc_archflag.m4
index 7c114cdd0907a28230c40265f72265bede5434e4..6d4feb1e0aab816d0830dcdfdd6d84d61575c8b2 100644
--- a/m4/ax_gcc_archflag.m4
+++ b/m4/ax_gcc_archflag.m4
@@ -109,7 +109,7 @@ case $host_cpu in
 	    *3?6[[cf]]?:*:*:*|*4?6[[56]]?:*:*:*) ax_gcc_arch="haswell core-avx2 core-avx-i corei7-avx corei7 core2 pentium-m pentium3 pentiumpro" ;;
 	    *3?6d?:*:*:*|*4?6f?:*:*:*) ax_gcc_arch="broadwell core-avx2 core-avx-i corei7-avx corei7 core2 pentium-m pentium3 pentiumpro" ;;
 	    *4?6[[de]]?:*:*:*) ax_gcc_arch="skylake core-avx2 core-avx-i corei7-avx corei7 core2 pentium-m pentium3 pentiumpro" ;;	
-            *9?6[[de]]?:*:*:*) ax_gcc_arch="kabylake core-avx2 core-avx-i corei7-avx corei7 core2 pentium-m pentium3 pentiumpro" ;;	
+            *9?6[[de]]?:*:*:*) ax_gcc_arch="kabylake core-avx2 core-avx-i corei7-avx corei7 core2 pentium-m pentium3 pentiumpro" ;;
 	    *1?6c?:*:*:*|*2?6[[67]]?:*:*:*|*3?6[[56]]?:*:*:*) ax_gcc_arch="bonnell atom core2 pentium-m pentium3 pentiumpro" ;;
 	    *3?67?:*:*:*|*[[45]]?6[[ad]]?:*:*:*) ax_gcc_arch="silvermont atom core2 pentium-m pentium3 pentiumpro" ;;
 	    *000?f[[012]]?:*:*:*|?f[[012]]?:*:*:*|f[[012]]?:*:*:*) ax_gcc_arch="pentium4 pentiumpro" ;;