OpenLDAP ITS#7363 cleanups [revised patch]

defined(BSD) breaks in strict ISO C mode.  Is there a symbol like
__BSD__ or __BSD to use instead?

Namespace-wise, "MDB_USE_POSIX_SEM" would be better.

MDB_FDATASYNC should not depend on USE_POSIX_SEM.


Patch follows, except:
Replace defined(BSD) in 1st patch with defined(__BSD__) or whatever.
Also, maybe we can drop __APPLE__ - it may #define __BSD__ too.
ANDROID should be something like __ANDROID__.  I can't test either.

########################################################################

Separate MDB_FDATASYNC from USE_POSIX_SEM.

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index 6be2103..16c44f3 100644
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -159,11 +159,8 @@
 #define UNLOCK_MUTEX_R(env)	sem_post((env)->me_rmutex)
 #define LOCK_MUTEX_W(env)	sem_wait((env)->me_wmutex)
 #define UNLOCK_MUTEX_W(env)	sem_post((env)->me_wmutex)
-#define MDB_FDATASYNC(fd)	fsync(fd)
 #else
-#ifdef ANDROID
-#define MDB_FDATASYNC(fd)	fsync(fd)
-#endif
+
 	/** Lock the reader mutex.
 	 */
 #define LOCK_MUTEX_R(env)	pthread_mutex_lock(&(env)->me_txns->mti_mutex)
@@ -230,7 +227,10 @@
 /** Function for flushing the data of a file. Define this to fsync
  *	if fdatasync() is not supported.
  */
-#ifndef MDB_FDATASYNC
+#ifdef MDB_FDATASYNC
+#elif defined(ANDROID) || defined(BSD) || defined(__APPLE__)
+# define MDB_FDATASYNC	fsync
+#else
 # define MDB_FDATASYNC	fdatasync
 #endif
 
########################################################################

USE_POSIX_SEM -> MDB_USE_POSIX_SEM.
    
Also join #ifdef WIN32/#endif/#ifdef MDB_USE_POSIX_SEM/#endif
into a more logical-looking #if/#elif/#endif.

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index e67df5a..b18ee68 100644
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -65,11 +65,11 @@
 #include <pthread.h>
 
 /* Use named semaphores if process-shared mutexes are not supported. */
-#if !defined(PTHREAD_PROCESS_SHARED) && !defined(USE_POSIX_SEM)
-#define USE_POSIX_SEM	1
+#if !defined(PTHREAD_PROCESS_SHARED) && !defined(MDB_USE_POSIX_SEM)
+#define MDB_USE_POSIX_SEM	1
 #endif
 
-#ifdef USE_POSIX_SEM
+#ifdef MDB_USE_POSIX_SEM
 #include <semaphore.h>
 #endif
 #endif
@@ -156,7 +156,7 @@
 #define	close(fd)	CloseHandle(fd)
 #define	munmap(ptr,len)	UnmapViewOfFile(ptr)
 #else
-#ifdef USE_POSIX_SEM
+#ifdef MDB_USE_POSIX_SEM
 #define LOCK_MUTEX_R(env)	sem_wait((env)->me_rmutex)
 #define UNLOCK_MUTEX_R(env)	sem_post((env)->me_rmutex)
 #define LOCK_MUTEX_W(env)	sem_wait((env)->me_wmutex)
@@ -178,7 +178,7 @@
 	/** Unlock the writer mutex.
 	 */
 #define UNLOCK_MUTEX_W(env)	pthread_mutex_unlock(&(env)->me_txns->mti_wmutex)
-#endif	/* USE_POSIX_SEM */
+#endif	/* MDB_USE_POSIX_SEM */
 
 	/** Get the error code for the last failed system function.
 	 */
@@ -203,7 +203,7 @@
 #define	GET_PAGESIZE(x)	((x) = sysconf(_SC_PAGE_SIZE))
 #endif
 
-#if defined(_WIN32) || defined(USE_POSIX_SEM)
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
 #define MNAME_LEN	32
 #else
 #define MNAME_LEN	(sizeof(pthread_mutex_t))
@@ -470,7 +470,7 @@ typedef struct MDB_txbody {
 	uint32_t	mtb_magic;
 		/** Version number of this lock file. Must be set to #MDB_VERSION. */
 	uint32_t	mtb_version;
-#if defined(_WIN32) || defined(USE_POSIX_SEM)
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
 	char	mtb_rmname[MNAME_LEN];
 #else
 		/** Mutex protecting access to this table.
@@ -503,7 +503,7 @@ typedef struct MDB_txninfo {
 		char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
 	} mt1;
 	union {
-#if defined(_WIN32) || defined(USE_POSIX_SEM)
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
 		char mt2_wmname[MNAME_LEN];
 #define	mti_wmname	mt2.mt2_wmname
 #else
@@ -919,9 +919,8 @@ struct MDB_env {
 #ifdef _WIN32
 	HANDLE		me_rmutex;		/* Windows mutexes don't reside in shared mem */
 	HANDLE		me_wmutex;
-#endif
-#ifdef USE_POSIX_SEM
-	sem_t		*me_rmutex;		/* Apple doesn't support shared mutexes */
+#elif defined(MDB_USE_POSIX_SEM)
+	sem_t		*me_rmutex;
 	sem_t		*me_wmutex;
 #endif
 };
@@ -2687,7 +2686,7 @@ mdb_env_excl_lock(MDB_env *env, int *excl)
 	return 0;
 }
 
-#if defined(_WIN32) || defined(USE_POSIX_SEM)
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
 /*
  * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
  *
@@ -2897,8 +2896,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
 			rc = ErrCode();
 			goto fail;
 		}
-#else	/* _WIN32 */
-#ifdef USE_POSIX_SEM
+#elif defined(MDB_USE_POSIX_SEM)
 		struct stat stbuf;
 		struct {
 			dev_t dev;
@@ -2935,7 +2933,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
 			rc = ErrCode();
 			goto fail;
 		}
-#else	/* USE_POSIX_SEM */
+#else	/* MDB_USE_POSIX_SEM */
 		pthread_mutexattr_t mattr;
 
 		pthread_mutexattr_init(&mattr);
@@ -2945,7 +2943,6 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
 		}
 		pthread_mutex_init(&env->me_txns->mti_mutex, &mattr);
 		pthread_mutex_init(&env->me_txns->mti_wmutex, &mattr);
-#endif	/* USE_POSIX_SEM */
 #endif	/* _WIN32 */
 		env->me_txns->mti_version = MDB_VERSION;
 		env->me_txns->mti_magic = MDB_MAGIC;
@@ -2979,8 +2976,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
 			rc = ErrCode();
 			goto fail;
 		}
-#endif
-#ifdef USE_POSIX_SEM
+#elif defined(MDB_USE_POSIX_SEM)
 		env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
 		if (env->me_rmutex == SEM_FAILED) {
 			rc = ErrCode();
@@ -3166,8 +3162,7 @@ mdb_env_close(MDB_env *env)
 		/* Windows automatically destroys the mutexes when
 		 * the last handle closes.
 		 */
-#else
-#ifdef USE_POSIX_SEM
+#elif defined(MDB_USE_POSIX_SEM)
 		sem_close(env->me_rmutex);
 		sem_close(env->me_wmutex);
 		{ int excl = 0;
@@ -3179,7 +3174,6 @@ mdb_env_close(MDB_env *env)
 			}
 		}
 #endif
-#endif
 		munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
 	}
 	close(env->me_lfd);