Add API function to check if the specified feature is enabled. (#1465)

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka rsipka.uszeged@partner.samsung.com

docs/02.API-REFERENCE.md

@@ -22,6 +22,18 @@ Possible types of an error:
  - JERRY_ERROR_TYPE - type error
  - JERRY_ERROR_URI - URI error
 
+## jerry_feature_t
+
+Possible compile time enabled feature types:
+
+ - JERRY_FEATURE_ERROR_MESSAGES - error messages
+ - JERRY_FEATURE_CPOINTER_32_BIT - 32 bit compressed pointers
+ - JERRY_FEATURE_MEM_STATS - memory statistics
+ - JERRY_FEATURE_PARSER_DUMP - parser byte-code dumps
+ - JERRY_FEATURE_REGEXP_DUMP - regexp byte-code dumps
+ - JERRY_FEATURE_SNAPSHOT_SAVE - saving snapshot files
+ - JERRY_FEATURE_SNAPSHOT_EXEC - executing snapshot files
+
 ## jerry_char_t
 
 **Summary**
@@ -917,6 +929,38 @@ jerry_value_is_undefined (const jerry_value_t value)
 
 - [jerry_release_value](#jerry_release_value)
 
+## jerry_is_feature_enabled
+
+**Summary**
+
+Returns whether the specified compile time feature is enabled.
+
+**Prototype**
+
+```c
+bool
+jerry_is_feature_enabled (const jerry_feature_t feature);
+```
+
+- `feature` - jerry feature
+- return value
+  - true, if the given `jerry_feature_t` is enabled
+  - false, otherwise
+
+**Example**
+
+```c
+{
+  ...
+  jerry_feature_t feature = JERRY_FEATURE_SNAPSHOT_SAVE;
+
+  if (jerry_is_feature_enabled (feature))
+  {
+    ...
+  }
+
+}
+```
 
 # Error flag manipulation functions