Initial skeleton of extension (#2)

* Added .gitignore

* Added initial attempt at autoconf config

* Skeleton C source

config.m4

@@ -0,0 +1,30 @@
+dnl
+dnl * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+dnl * SPDX-License-Identifier: Apache-2.0.
+dnl
+
+PHP_ARG_WITH(awscrt)
+
+if test "$PHP_AWSCRT" != "no"; then
+    AC_MSG_CHECKING([for libcrypto])
+    for search_path in "$AWS_LIBCRYTO_INSTALL" "$PHP_AWSCRT/build/deps/openssl" /opt/openssl /usr/local /usr; do
+        if test -f "$search_path/include/openssl/crypto.h"; then
+            LIBCRYPTO_PATH=$search_path
+            break
+        fi
+    done
+    if test -z "$LIBCRYPTO_PATH"; then
+        AC_MSG_ERROR([not found])
+    fi
+
+    AC_MSG_RESULT([found at $LIBCRYPTO_PATH])
+
+    PHP_ADD_INCLUDE($LIBCRYPTO_PATH/include)
+    dnl PHP_ADD_LIBPATH($LIBCRYPTO_PATH/lib)
+    PHP_ADD_LIBRARY_WITH_PATH(:libcrypto.a, $LIBCRYPTO_PATH/lib, AWSCRT_SHARED_LIBADD)
+
+    AWSCRT_SOURCES=src/*.c
+
+    PHP_NEW_EXTENSION(awscrt, $AWSCRT_SOURCES, $ext_shared)
+    PHP_SUBST(AWSCRT_SHARED_LIBADD)
+fi