fix: typo: add openssl include (#19)

Author: kingluo

Makefile

@@ -11,7 +11,7 @@ XMLSEC_VER = 1.2.28
 
 CC = gcc
 CFLAGS_SAML = -g -fPIC -O2 -fcommon
-XMLSEC1_CFLAGS = -D__XMLSEC_FUNCTION__=__func__ -DXMLSEC_NO_SIZE_T -DXMLSEC_NO_GOST=1 -DXMLSEC_NO_GOST2012=1 -DXMLSEC_NO_CRYPTO_DYNAMIC_LOADING=1 -Ixmlsec1-$(XMLSEC_VER)/include/ -I/usr/include/libxml2 -DXMLSEC_CRYPTO_OPENSSL=1 -I$(OPENSSL_DIR)/inc
+XMLSEC1_CFLAGS = -D__XMLSEC_FUNCTION__=__func__ -DXMLSEC_NO_SIZE_T -DXMLSEC_NO_GOST=1 -DXMLSEC_NO_GOST2012=1 -DXMLSEC_NO_CRYPTO_DYNAMIC_LOADING=1 -Ixmlsec1-$(XMLSEC_VER)/include/ -I/usr/include/libxml2 -DXMLSEC_CRYPTO_OPENSSL=1 -I$(OPENSSL_DIR)/include
 CFLAGS_ALL=$(CFLAGS_SAML) -Wall -Werror -std=c99 $(XMLSEC1_CFLAGS)
 LIBFLAG = -shared
 LDFLAGS = -g -O2