diff --git a/build-libssp.sh b/build-libssp.sh
index e9d1a04..774d74d 100755
--- a/build-libssp.sh
+++ b/build-libssp.sh
@@ -22,7 +22,7 @@ if [ $# -lt 1 ]; then
 fi
 
 MAKE=make
-if [ "$(which gmake)" != "" ]; then
+if [ -n "$(which gmake)" ]; then
     MAKE=gmake
 fi
 
diff --git a/build-mingw-w64-tools.sh b/build-mingw-w64-tools.sh
index 275126c..6d55bc4 100755
--- a/build-mingw-w64-tools.sh
+++ b/build-mingw-w64-tools.sh
@@ -49,7 +49,7 @@ fi
 cd mingw-w64
 
 MAKE=make
-if [ "$(which gmake)" != "" ]; then
+if [ -n "$(which gmake)" ]; then
     MAKE=gmake
 fi
 
diff --git a/build-mingw-w64.sh b/build-mingw-w64.sh
index 9abf7bb..844ec6b 100755
--- a/build-mingw-w64.sh
+++ b/build-mingw-w64.sh
@@ -62,7 +62,7 @@ fi
 [ -z "$CHECKOUT_ONLY" ] || exit 0
 
 MAKE=make
-if [ "$(which gmake)" != "" ]; then
+if [ -n "$(which gmake)" ]; then
     MAKE=gmake
 fi