Use pthread rwlocks by default

aclocal.m4

@@ -100,7 +100,7 @@ dnl Check to see whether a particular set of modules exists. Similar to
 dnl PKG_CHECK_MODULES(), but does not set variables or print errors.
 dnl
 dnl Please remember that m4 expands AC_REQUIRE([PKG_PROG_PKG_CONFIG])
-dnl only at the first occurrence in configure.ac, so if the first place
+dnl only at the first occurence in configure.ac, so if the first place
 dnl it's called might be skipped (such as if it is within an "if", you
 dnl have to call PKG_CHECK_EXISTS manually
 AC_DEFUN([PKG_CHECK_EXISTS],

configure

@@ -1625,8 +1625,9 @@ Optional Features:
   --enable-devpoll        use /dev/poll when available [default=yes]
   --disable-geoip         support GeoIP2 geolocation ACLs if available
                           [default=yes]
-  --enable-pthread-rwlock use pthread rwlock instead of internal rwlock
-                          implementation (EXPERIMENTAL)
+  --disable-pthread-rwlock
+                          use internal rwlock implementation instead of
+                          pthread rwlock
   --enable-fips-mode      enable FIPS mode in OpenSSL library [default=no]
   --enable-native-pkcs11  use native PKCS11 for public-key crypto [default=no]
   --enable-backtrace      log stack backtrace on abort [default=yes]
@@ -16040,13 +16041,13 @@ esac
 
 
 #
-# Do we want to use pthread rwlock? (useful for ThreadSanitizer)
+# Do we want to use pthread rwlock?
 #
 # Check whether --enable-pthread_rwlock was given.
 if test "${enable_pthread_rwlock+set}" = set; then :
   enableval=$enable_pthread_rwlock;
 else
-  enable_pthread_rwlock=no
+  enable_pthread_rwlock=yes
 fi
 
 

configure.ac

@@ -716,12 +716,12 @@ esac
 AC_SUBST(INSTALL_LIBRARY)
 
 #
-# Do we want to use pthread rwlock? (useful for ThreadSanitizer)
+# Do we want to use pthread rwlock?
 #
 AC_ARG_ENABLE([pthread_rwlock],
-	      [AS_HELP_STRING([--enable-pthread-rwlock],
-			      [use pthread rwlock instead of internal rwlock implementation (EXPERIMENTAL)])],
-	      [], [enable_pthread_rwlock=no])
+	      [AS_HELP_STRING([--disable-pthread-rwlock],
+			      [use internal rwlock implementation instead of pthread rwlock])],
+	      [], [enable_pthread_rwlock=yes])
 
 AS_IF([test "$enable_pthread_rwlock" = "yes"],
       [AC_CHECK_FUNCS([pthread_rwlock_rdlock], [],