Add compiler.has_define

Adds a new method to the compiler object, has_define.
This makes it possible to check if a preprocessor macro/define
is set or not.

This is especially helpful if the define in question is empty,
for example:

  #define MESON_EMPTY_DEFINE

This would yield the same results as a missing define with
the existing get_define method, as it would return an empty
string for both cases. Therefore this additional method is
needed.

1 files changed, 11 insertions, 0 deletions

diff --git a/docs/yaml/objects/compiler.yaml b/docs/yaml/objects/compiler.yaml
index d5d7df5..977cbdf 100644
--- a/docs/yaml/objects/compiler.yaml
+++ b/docs/yaml/objects/compiler.yaml
@@ -327,6 +327,17 @@ methods:
       type: str
       description: The define to check.
 
+- name: has_define
+  returns: bool
+  since: 1.3.0
+  description: |
+    Returns true if the given preprocessor symbol is *defined*.
+  kwargs_inherit: compiler._common
+  posargs:
+    definename:
+      type: str
+      description: The define to check.
+
 - name: compiles
   returns: bool
   description: Returns true if the code compiles.