diff --git a/sci-mathematics/stp/stp-2.3.3-r3.ebuild b/sci-mathematics/stp/stp-2.3.3-r3.ebuild
index ae62721212d22..bd4d40fd22d40 100644
--- a/sci-mathematics/stp/stp-2.3.3-r3.ebuild
+++ b/sci-mathematics/stp/stp-2.3.3-r3.ebuild
@@ -100,12 +100,18 @@ src_configure() {
 	fi
 
 	local -a mycmakeargs=(
-		-DTEST_C_API=OFF  # C API test fail
 		-DNOCRYPTOMINISAT=$(usex cryptominisat 'OFF' 'ON')  # double negation
 		-DENABLE_PYTHON_INTERFACE=$(usex python)
 		-DENABLE_ASSERTIONS=$(usex test)
 		-DENABLE_TESTING=$(usex test)
 	)
+
+	if use test ; then
+		mycmakeargs+=(
+			-DTEST_C_API=OFF  # C API test fail
+		)
+	fi
+
 	cmake_src_configure
 }
 
diff --git a/sci-mathematics/stp/stp-2.3.4.ebuild b/sci-mathematics/stp/stp-2.3.4.ebuild
index ab1cbf96c2d22..ab792a8ff3cd8 100644
--- a/sci-mathematics/stp/stp-2.3.4.ebuild
+++ b/sci-mathematics/stp/stp-2.3.4.ebuild
@@ -78,9 +78,6 @@ src_configure() {
 	fi
 
 	local -a mycmakeargs=(
-		# -DGTEST_PREFIX="${BROOT}/usr/$(get_libdir)/cmake/GTest"
-
-		-DTEST_C_API=OFF  # C API test fail
 		-DUSE_RISS=OFF
 
 		# Cryptominisat switches
@@ -91,6 +88,13 @@ src_configure() {
 		-DENABLE_ASSERTIONS=$(usex test)
 		-DENABLE_TESTING=$(usex test)
 	)
+
+	if use test ; then
+		mycmakeargs+=(
+			-DTEST_C_API=OFF  # C API test fail
+		)
+	fi
+
 	cmake_src_configure
 }