wt-status.c: set commitable bit if there is a meaningful merge.

diff --git a/git-compat-util.h b/git-compat-util.h
index bc8fc8cf854e96badfdf4d96673d33b799207ff3..af5af226807ed2da5a2630d258aac14953811dd4 100644 (file)
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -3,6 +3,23 @@
 
 #define _FILE_OFFSET_BITS 64
 
+
+/* Derived from Linux "Features Test Macro" header
+ * Convenience macros to test the versions of gcc (or
+ * a compatible compiler).
+ * Use them like this:
+ *  #if GIT_GNUC_PREREQ (2,8)
+ *   ... code requiring gcc 2.8 or later ...
+ *  #endif
+*/
+#if defined(__GNUC__) && defined(__GNUC_MINOR__)
+# define GIT_GNUC_PREREQ(maj, min) \
+       ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
+#else
+ #define GIT_GNUC_PREREQ(maj, min) 0
+#endif
+
+
 #ifndef FLEX_ARRAY
 /*
  * See if our compiler is known to support flexible array members.
@@ -25,7 +42,40 @@
 #endif
 #endif
 
-#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
+
+/*
+ * BUILD_ASSERT_OR_ZERO - assert a build-time dependency, as an expression.
+ * @cond: the compile-time condition which must be true.
+ *
+ * Your compile will fail if the condition isn't true, or can't be evaluated
+ * by the compiler.  This can be used in an expression: its value is "0".
+ *
+ * Example:
+ *     #define foo_to_char(foo)                                        \
+ *              ((char *)(foo)                                         \
+ *               + BUILD_ASSERT_OR_ZERO(offsetof(struct foo, string) == 0))
+ */
+#define BUILD_ASSERT_OR_ZERO(cond) \
+       (sizeof(char [1 - 2*!(cond)]) - 1)
+
+#if GIT_GNUC_PREREQ(3, 1)
+ /* &arr[0] degrades to a pointer: a different type from an array */
+# define BARF_UNLESS_AN_ARRAY(arr)                                             \
+       BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
+                                                          __typeof__(&(arr)[0])))
+#else
+# define BARF_UNLESS_AN_ARRAY(arr) 0
+#endif
+/*
+ * ARRAY_SIZE - get the number of elements in a visible array
+ *  <at> x: the array whose size you want.
+ *
+ * This does not work on pointers, or arrays declared as [], or
+ * function parameters.  With correct compiler support, such usage
+ * will cause a build error (see the build_assert_or_zero macro).
+ */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_UNLESS_AN_ARRAY(x))
+
 #define bitsizeof(x)  (CHAR_BIT * sizeof(x))
 
 #define maximum_signed_value_of_type(a) \
@@ -665,6 +715,7 @@ extern char *xstrndup(const char *str, size_t len);
 extern void *xrealloc(void *ptr, size_t size);
 extern void *xcalloc(size_t nmemb, size_t size);
 extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
+extern void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
 extern ssize_t xread(int fd, void *buf, size_t len);
 extern ssize_t xwrite(int fd, const void *buf, size_t len);
 extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);