feat(agent): Add RabbitMQ instrumentation using the php-amqplib library

agent/Makefile.frag

@@ -93,6 +93,7 @@ TEST_BINARIES = \
 	tests/test_internal_instrument \
 	tests/test_hash \
 	tests/test_lib_aws_sdk_php \
+        tests/test_lib_php_amqplib \
 	tests/test_memcached \
 	tests/test_mongodb \
 	tests/test_monolog \

agent/config.m4

@@ -231,7 +231,7 @@ if test "$PHP_NEWRELIC" = "yes"; then
   LIBRARIES="lib_aws_sdk_php.c lib_monolog.c lib_doctrine2.c lib_guzzle3.c \
   lib_guzzle4.c lib_guzzle6.c lib_guzzle_common.c \
   lib_mongodb.c lib_phpunit.c lib_predis.c lib_zend_http.c \
-  lib_composer.c"
+  lib_composer.c lib_php_amqplib.c"
   PHP_NEW_EXTENSION(newrelic, $FRAMEWORKS $LIBRARIES $NEWRELIC_AGENT, $ext_shared,, $(NEWRELIC_CFLAGS))
 
   PHP_SUBST(NEWRELIC_CFLAGS)

agent/fw_hooks.h

@@ -46,6 +46,7 @@ extern void nr_guzzle4_enable(TSRMLS_D);
 extern void nr_guzzle6_enable(TSRMLS_D);
 extern void nr_laminas_http_enable(TSRMLS_D);
 extern void nr_mongodb_enable(TSRMLS_D);
+extern void nr_php_amqplib_enable();
 extern void nr_phpunit_enable(TSRMLS_D);
 extern void nr_predis_enable(TSRMLS_D);
 extern void nr_zend_http_enable(TSRMLS_D);

agent/lib_aws_sdk_php.c

@@ -429,6 +429,12 @@ void nr_lib_aws_sdk_php_handle_version() {
   zval retval;
   int result = FAILURE;
 
+  /*
+   * The following block initializes nr_aws_sdk_version to the empty string.
+   * If it is able to extract the version, nr_aws_sdk_version is set to that.
+   * Nothing is needed in the catch block.
+   * The final return will either return a proper version or an empty string.
+   */
   result = zend_eval_string(
       "(function() {"
       "     $nr_aws_sdk_version = '';"