Add automatic generation of headers

- The 'stripdecls.py' script replaces declarations in all headers by includes to
  generated headers.
  `ag '#\s*if(?!ndef NEOVIM_).*((?!#\s*endif).*\n)*#ifdef INCLUDE_GENERATED'`
  was used for this.
- Add and integrate gendeclarations.lua into the build system to generate the
  required includes.
- Add -Wno-unused-function
- Made a bunch of old-style definitions ANSI

This adds a requirement: all type and structure definitions must be present
before INCLUDE_GENERATED_DECLARATIONS-protected include.

Warning: mch_expandpath (path.h.generated.h) was moved manually. So far it is
the only exception.

1 files changed, 128 insertions, 63 deletions

diff --git a/src/nvim/func_attr.h b/src/nvim/func_attr.h
index 6e7149e8fb..68384e1b61 100644
--- a/src/nvim/func_attr.h
+++ b/src/nvim/func_attr.h
@@ -1,5 +1,20 @@
-#ifndef NVIM_FUNC_ATTR_H
-#define NVIM_FUNC_ATTR_H
+// If DEFINE_FUNC_ATTRIBUTES macro is not defined then all function attributes 
+// are defined as empty values.
+//
+// If DO_NOT_DEFINE_EMPTY_ATTRIBUTES then empty macros are not defined. Thus 
+// undefined DEFINE_FUNC_ATTRIBUTES and defined DO_NOT_DEFINE_EMPTY_ATTRIBUTES 
+// leaves file with untouched FUNC_ATTR_* macros. This variant is used for 
+// scripts/gendeclarations.lua.
+//
+// Empty macros are used for *.c files. (undefined DEFINE_FUNC_ATTRIBUTES and 
+// undefined DO_NOT_DEFINE_EMPTY_ATTRIBUTES)
+//
+// Macros defined as __attribute__((*)) are used by generated header files. 
+// (defined DEFINE_FUNC_ATTRIBUTES and undefined 
+// DO_NOT_DEFINE_EMPTY_ATTRIBUTES)
+//
+// Defined DEFINE_FUNC_ATTRIBUTES and defined DO_NOT_DEFINE_EMPTY_ATTRIBUTES is 
+// not used by anything.
 
 // gcc and clang expose their version as follows:
 //
@@ -21,90 +36,140 @@
 // $ gcc -E -dM - </dev/null
 // $ echo | clang -dM -E -
 
-#ifdef __GNUC__
-  // place defines for all gnulikes here, for now that's gcc, clang and
-  // intel.
-
-  // place these after the argument list of the function declaration
-  // (not definition), like so:
-  // void myfunc(void) FUNC_ATTR_ALWAYS_INLINE;
-  #define FUNC_ATTR_MALLOC __attribute__((malloc))
-  #define FUNC_ATTR_ALLOC_ALIGN(x) __attribute__((alloc_align(x)))
-  #define FUNC_ATTR_PURE __attribute__ ((pure))
-  #define FUNC_ATTR_CONST __attribute__((const))
-  #define FUNC_ATTR_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
-  #define FUNC_ATTR_ALWAYS_INLINE __attribute__((always_inline))
-  #define FUNC_ATTR_UNUSED __attribute__((unused))
-
-  #ifdef __clang__
-    // clang only
-  #elif defined(__INTEL_COMPILER)
-    // intel only
-  #else
-    #define GCC_VERSION \
-           (__GNUC__ * 10000 + \
-            __GNUC_MINOR__ * 100 + \
-            __GNUC_PATCHLEVEL__)
-    // gcc only
-    #define FUNC_ATTR_ALLOC_SIZE(x) __attribute__((alloc_size(x)))
-    #define FUNC_ATTR_ALLOC_SIZE_PROD(x,y) __attribute__((alloc_size(x,y)))
-    #define FUNC_ATTR_NONNULL_ALL __attribute__((nonnull))
-    #define FUNC_ATTR_NONNULL_ARG(...) __attribute__((nonnull(__VA_ARGS__)))
-    #if GCC_VERSION >= 40900
-      #define FUNC_ATTR_NONNULL_RET __attribute__((returns_nonnull))
-    #endif
-  #endif
+#ifdef FUNC_ATTR_MALLOC
+  #undef FUNC_ATTR_MALLOC
 #endif
 
-// define function attributes that haven't been defined for this specific
-// compiler.
-
-#ifndef FUNC_ATTR_MALLOC
-  #define FUNC_ATTR_MALLOC
+#ifdef FUNC_ATTR_ALLOC_SIZE
+  #undef FUNC_ATTR_ALLOC_SIZE
 #endif
 
-#ifndef FUNC_ATTR_ALLOC_SIZE
-  #define FUNC_ATTR_ALLOC_SIZE(x)
+#ifdef FUNC_ATTR_ALLOC_SIZE_PROD
+  #undef FUNC_ATTR_ALLOC_SIZE_PROD
 #endif
 
-#ifndef FUNC_ATTR_ALLOC_SIZE_PROD
-  #define FUNC_ATTR_ALLOC_SIZE_PROD(x,y)
+#ifdef FUNC_ATTR_ALLOC_ALIGN
+  #undef FUNC_ATTR_ALLOC_ALIGN
 #endif
 
-#ifndef FUNC_ATTR_ALLOC_ALIGN
-  #define FUNC_ATTR_ALLOC_ALIGN(x)
+#ifdef FUNC_ATTR_PURE
+  #undef FUNC_ATTR_PURE
 #endif
 
-#ifndef FUNC_ATTR_PURE
-  #define FUNC_ATTR_PURE
+#ifdef FUNC_ATTR_CONST
+  #undef FUNC_ATTR_CONST
 #endif
 
-#ifndef FUNC_ATTR_CONST
-  #define FUNC_ATTR_CONST
+#ifdef FUNC_ATTR_WARN_UNUSED_RESULT
+  #undef FUNC_ATTR_WARN_UNUSED_RESULT
 #endif
 
-#ifndef FUNC_ATTR_WARN_UNUSED_RESULT
-  #define FUNC_ATTR_WARN_UNUSED_RESULT
+#ifdef FUNC_ATTR_ALWAYS_INLINE
+  #undef FUNC_ATTR_ALWAYS_INLINE
 #endif
 
-#ifndef FUNC_ATTR_ALWAYS_INLINE
-  #define FUNC_ATTR_ALWAYS_INLINE
+#ifdef FUNC_ATTR_UNUSED
+  #undef FUNC_ATTR_UNUSED
 #endif
 
-#ifndef FUNC_ATTR_UNUSED
-  #define FUNC_ATTR_UNUSED
+#ifdef FUNC_ATTR_NONNULL_ALL
+  #undef FUNC_ATTR_NONNULL_ALL
 #endif
 
-#ifndef FUNC_ATTR_NONNULL_ALL
-  #define FUNC_ATTR_NONNULL_ALL
+#ifdef FUNC_ATTR_NONNULL_ARG
+  #undef FUNC_ATTR_NONNULL_ARG
 #endif
 
-#ifndef FUNC_ATTR_NONNULL_ARG
-  #define FUNC_ATTR_NONNULL_ARG(...)
+#ifdef FUNC_ATTR_NONNULL_RET
+  #undef FUNC_ATTR_NONNULL_RET
 #endif
 
-#ifndef FUNC_ATTR_NONNULL_RET
-  #define FUNC_ATTR_NONNULL_RET
+#ifdef DEFINE_FUNC_ATTRIBUTES
+  #ifdef __GNUC__
+    // place defines for all gnulikes here, for now that's gcc, clang and
+    // intel.
+
+    // place these after the argument list of the function declaration
+    // (not definition), like so:
+    // void myfunc(void) FUNC_ATTR_ALWAYS_INLINE;
+    #define FUNC_ATTR_MALLOC __attribute__((malloc))
+    #define FUNC_ATTR_ALLOC_ALIGN(x) __attribute__((alloc_align(x)))
+    #define FUNC_ATTR_PURE __attribute__ ((pure))
+    #define FUNC_ATTR_CONST __attribute__((const))
+    #define FUNC_ATTR_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
+    #define FUNC_ATTR_ALWAYS_INLINE __attribute__((always_inline))
+    #define FUNC_ATTR_UNUSED __attribute__((unused))
+
+    #ifdef __clang__
+      // clang only
+    #elif defined(__INTEL_COMPILER)
+      // intel only
+    #else
+      #define GCC_VERSION \
+            (__GNUC__ * 10000 + \
+              __GNUC_MINOR__ * 100 + \
+              __GNUC_PATCHLEVEL__)
+      // gcc only
+      #define FUNC_ATTR_ALLOC_SIZE(x) __attribute__((alloc_size(x)))
+      #define FUNC_ATTR_ALLOC_SIZE_PROD(x,y) __attribute__((alloc_size(x,y)))
+      #define FUNC_ATTR_NONNULL_ALL __attribute__((nonnull))
+      #define FUNC_ATTR_NONNULL_ARG(...) __attribute__((nonnull(__VA_ARGS__)))
+      #if GCC_VERSION >= 40900
+        #define FUNC_ATTR_NONNULL_RET __attribute__((returns_nonnull))
+      #endif
+    #endif
+  #endif
 #endif
 
-#endif // NVIM_FUNC_ATTR_H
+#ifndef DO_NOT_DEFINE_EMPTY_ATTRIBUTES
+  // define function attributes that haven't been defined for this specific
+  // compiler.
+
+  #ifndef FUNC_ATTR_MALLOC
+    #define FUNC_ATTR_MALLOC
+  #endif
+
+  #ifndef FUNC_ATTR_ALLOC_SIZE
+    #define FUNC_ATTR_ALLOC_SIZE(x)
+  #endif
+
+  #ifndef FUNC_ATTR_ALLOC_SIZE_PROD
+    #define FUNC_ATTR_ALLOC_SIZE_PROD(x,y)
+  #endif
+
+  #ifndef FUNC_ATTR_ALLOC_ALIGN
+    #define FUNC_ATTR_ALLOC_ALIGN(x)
+  #endif
+
+  #ifndef FUNC_ATTR_PURE
+    #define FUNC_ATTR_PURE
+  #endif
+
+  #ifndef FUNC_ATTR_CONST
+    #define FUNC_ATTR_CONST
+  #endif
+
+  #ifndef FUNC_ATTR_WARN_UNUSED_RESULT
+    #define FUNC_ATTR_WARN_UNUSED_RESULT
+  #endif
+
+  #ifndef FUNC_ATTR_ALWAYS_INLINE
+    #define FUNC_ATTR_ALWAYS_INLINE
+  #endif
+
+  #ifndef FUNC_ATTR_UNUSED
+    #define FUNC_ATTR_UNUSED
+  #endif
+
+  #ifndef FUNC_ATTR_NONNULL_ALL
+    #define FUNC_ATTR_NONNULL_ALL
+  #endif
+
+  #ifndef FUNC_ATTR_NONNULL_ARG
+    #define FUNC_ATTR_NONNULL_ARG(...)
+  #endif
+
+  #ifndef FUNC_ATTR_NONNULL_RET
+    #define FUNC_ATTR_NONNULL_RET
+  #endif
+#endif