add-path modification for building on Horizon (#3423)

* small fix to add-path so that only one set of flags is added for each library

* tab to spaces

Makefile

@@ -56,9 +56,10 @@ define add-path
 ifneq ("$(wildcard $(1)/lib64)","")
   INCLUDE_FLAGS += -I$(1)/include -L$(1)/lib64
   CHPL_FLAGS    += -I$(1)/include -L$(1)/lib64 --ldflags="-Wl,-rpath,$(1)/lib64"
+else
+  INCLUDE_FLAGS += -I$(1)/include -L$(1)/lib
+  CHPL_FLAGS    += -I$(1)/include -L$(1)/lib --ldflags="-Wl,-rpath,$(1)/lib"
 endif
-INCLUDE_FLAGS += -I$(1)/include -L$(1)/lib
-CHPL_FLAGS    += -I$(1)/include -L$(1)/lib --ldflags="-Wl,-rpath,$(1)/lib"
 endef
 # Usage: $(eval $(call add-path,/home/user/anaconda3/envs/arkouda))
 #                               ^ no space after comma