Use command -v in favor of which

--- a/Makerules
+++ b/Makerules
@@ -170,7 +170,7 @@
   ifneq ($(ARCHFLAGS),)
     $(warning "MacOS with ARCHFLAGS set. Assuming we are building for arm64, and setting HAVE_LIBCRYPTO to no.")
     HAVE_LIBCRYPTO := no
-  else ifeq (, $(shell which pkg-config))
+  else ifeq (, $(shell command -v pkg-config))
     $(warning "No pkg-config found, install it for proper integration of libcrypto")
   else
     HAVE_LIBCRYPTO := $(shell pkg-config --exists 'libcrypto >= 1.1.0' && echo yes)