Clean up build configuration

4 files changed, 43 insertions, 17 deletions

diff --git a/src/.clang-tidy b/src/.clang-tidy
index bcf65be..66ba28d 100644
--- a/src/.clang-tidy
+++ b/src/.clang-tidy
@@ -4,9 +4,6 @@ Checks: >
   -*-uppercase-literal-suffix,
   -altera-*,
   -bugprone-easily-swappable-parameters,
-  -bugprone-reserved-identifier,
-  -cert-dcl37-c,
-  -cert-dcl51-cpp,
   -clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling,
   -hicpp-multiway-paths-covered,
   -llvm-header-guard,
diff --git a/src/allocator.c b/src/allocator.c
index 2df0b90..ca91803 100644
--- a/src/allocator.c
+++ b/src/allocator.c
@@ -1,13 +1,12 @@
 // Copyright 2011-2021 David Robillard <d@drobilla.net>
 // SPDX-License-Identifier: ISC
 
-#define _POSIX_C_SOURCE 200809L
-
-#include "zix_config.h"
-
 #include "zix/allocator.h"
+
 #include "zix/attributes.h"
 
+#include "zix_config.h"
+
 #ifdef _WIN32
 #  define WIN32_LEAN_AND_MEAN 1
 #  include <malloc.h>
diff --git a/src/ring.c b/src/ring.c
index a464428..d5b942b 100644
--- a/src/ring.c
+++ b/src/ring.c
@@ -3,10 +3,12 @@
 
 #include "zix/ring.h"
 
+#include "zix_config.h"
+
 #include <stdlib.h>
 #include <string.h>
 
-#ifdef HAVE_MLOCK
+#if USE_MLOCK
 #  include <sys/mman.h>
 #  define ZIX_MLOCK(ptr, size) mlock((ptr), (size))
 #elif defined(_WIN32)
diff --git a/src/zix_config.h b/src/zix_config.h
index 832b50f..7be46e4 100644
--- a/src/zix_config.h
+++ b/src/zix_config.h
@@ -1,15 +1,26 @@
-// Copyright 2021 David Robillard <d@drobilla.net>
+// Copyright 2021-2022 David Robillard <d@drobilla.net>
 // SPDX-License-Identifier: ISC
 
 /*
   Configuration header that defines reasonable defaults at compile time.
 
-  This allows compile-time configuration from the command line (typically via
-  the build system) while still allowing the source to be built without any
-  configuration.  The build system can define ZIX_NO_DEFAULT_CONFIG to disable
-  defaults, in which case it must define things like HAVE_FEATURE to enable
-  features.  The design here ensures that compiler warnings or
-  include-what-you-use will catch any mistakes.
+  This allows compile-time configuration from the command line, while still
+  allowing the source to be built "as-is" without any configuration.  The idea
+  is to support an advanced build system with configuration checks, while still
+  allowing the code to be simply "thrown at a compiler" with features
+  determined from the compiler or system headers.  Everything can be
+  overridden, so it should never be necessary to edit this file to build
+  successfully.
+
+  To ensure that all configure checks are performed, the build system can
+  define ZIX_NO_DEFAULT_CONFIG to disable defaults.  In this case, it must
+  define all HAVE_FEATURE symbols below to 1 or 0 to enable or disable
+  features.  Any missing definitions will generate a compiler warning.
+
+  To ensure that this header is always included properly, all code that uses
+  configuration variables includes this header and checks their value with #if
+  (not #ifdef).  Variables like USE_FEATURE are internal and should never be
+  defined on the command line.
 */
 
 #ifndef ZIX_CONFIG_H
@@ -28,10 +39,21 @@
 #    endif
 #  endif
 
+// POSIX.1-2001: mlock()
+#  ifndef HAVE_MLOCK
+#    if defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112L
+#      define HAVE_MLOCK 1
+#    else
+#      define HAVE_MLOCK 0
+#    endif
+#  endif
+
 // POSIX.1-2001: posix_memalign()
 #  ifndef HAVE_POSIX_MEMALIGN
 #    if defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112L
-#      define HAVE_POSIX_MEMALIGN
+#      define HAVE_POSIX_MEMALIGN 1
+#    else
+#      define HAVE_POSIX_MEMALIGN 0
 #    endif
 #  endif
 
@@ -45,7 +67,13 @@
   if the build system defines them all.
 */
 
-#ifdef HAVE_POSIX_MEMALIGN
+#if HAVE_MLOCK
+#  define USE_MLOCK 1
+#else
+#  define USE_MLOCK 0
+#endif
+
+#if HAVE_POSIX_MEMALIGN
 #  define USE_POSIX_MEMALIGN 1
 #else
 #  define USE_POSIX_MEMALIGN 0