Fix: detect openssl installed from homebrew on macOS

bin/ci

@@ -86,7 +86,7 @@ format() {
 prepare_build() {
   on_linux verify_linux_environment
 
-  on_osx brew install crystal
+  on_osx brew install crystal openssl
 
   # Make sure binaries from llvm are available in PATH
   on_osx brew install jq

src/openssl/version.sh

@@ -10,6 +10,22 @@ else
     OPENSSL_CFLAGS="-I$OPENSSL_DIR/include"
 fi
 
+if [ -z $OPENSSL_CFLAGS ] && [ "`uname -s`" = "Darwin" ]; then
+    OPENSSL_DIR=/usr/local/opt/openssl
+
+    # check default homebrew install directory (fast):
+    if [ -d "$OPENSSL_DIR/include" ]; then
+        OPENSSL_CFLAGS="-I$OPENSSL_DIR/include"
+    else
+        # ask homebrew (slower):
+        OPENSSL_DIR=$(command -v brew > /dev/null && brew --prefix openssl)
+
+        if [ -n "$OPENSSL_DIR" ] && [ -d "$OPENSSL_DIR/include" ]; then
+            OPENSSL_CFLAGS="-I$OPENSSL_DIR/include"
+        fi
+    fi
+fi
+
 # extract version numbers from OpenSSL/LibreSSL C headers:
 LIBRESSL_VERSION_NUMBER=$(printf "#include <openssl/opensslv.h>\nLIBRESSL_VERSION_NUMBER" | ${CC:-cc} $OPENSSL_CFLAGS -E - 2> /dev/null | tail -n 1)
 OPENSSL_VERSION_NUMBER=$(printf "#include <openssl/opensslv.h>\nOPENSSL_VERSION_NUMBER" | ${CC:-cc} $OPENSSL_CFLAGS -E - 2> /dev/null | tail -n 1)