Complete built-in checks support, add few checks

README.md

@@ -3,13 +3,47 @@
 GNU Autoconf emulation build system module for `build2`.
 
 Specifically, this module provides an [`in`][module-in]-based rule for
-processing `config.h.in` files. Besides the Autoconf flavor, it also supports
-CMake and Meson variants.
+processing `config.h.in` files. Besides the Autoconf special line flavor
+(`#undef`), it also supports the CMake (`#cmakedefine`) and Meson
+(`#mesondefine`) variants.
 
-Similar to Autoconf, the module provides built-in support for a number of
+Similar to Autoconf, this module provides built-in support for a number of
 common `HAVE_*` configuration options. However, the values of these options
 are not discovered by dynamic probing, such as trying to compile a test
-program to check if the header is present. Instead, they are set to static
-expected values based on the platform/compiler macros.
+program to check if the feature is present. Instead, they are set to static
+expected values based on the platform/compiler macros (see note at the
+beginning of [Project Configuration][proj-config] for rationale).
+
+See [`libbuild2/autoconf/checks/`][checks] for the list of available build-in
+configuration options.
+
+## Adding new configuration options.
+
+To add a new configuration option `<NAME>` simply create the `<NAME>.h` header
+file with the corresponding check and place it into
+[`libbuild2/autoconf/checks/`][checks] (use existing checks for inspiration).
+
+The first line in this header file must be in the form:
+
+```
+// <NAME>
+```
+
+Subsequent lines should be C-style comments or preprocessor directives that
+`#define` or `#undef` `<NAME>` depending on whether the feature is available
+(though there can be idiosyncrasies; see `const.h`, for example).  Note that
+there should be no double-quotes or backslashes except for line
+continuations. For example:
+
+```
+// HAVE_FOO
+#ifndef _WIN32
+#  define HAVE_FOO 1
+#else
+#  undef HAVE_FOO /* No foo on Windows. */
+#endif
+```
 
 [module-in]: https://build2.org/build2/doc/build2-build-system-manual.xhtml#module-in
+[proj-config]: https://build2.org/build2/doc/build2-build-system-manual.xhtml#proj-config
+[checks]: https://github.com/build2/libbuild2-autoconf/tree/master/libbuild2-autoconf/libbuild2/autoconf/checks/

libbuild2-autoconf-tests/basics/testscript

@@ -43,8 +43,8 @@ cat <<EOI >=config.h.in;
   #undef CUSTOM_LINE
   #undef CUSTOM_BLOCK
 
-  #undef HAVE_TEST_DUMMY1_H
-  #undef HAVE_TEST_DUMMY2_H
+  #undef zzz_TEST_DUMMY1_H
+  #undef zzz_TEST_DUMMY2_H
   EOI
 $* <<EOI &config.h &config.h.d;
   ./: h{config}: in{config}
@@ -64,7 +64,7 @@ $* <<EOI &config.h &config.h.d;
   #endif
   '
 
-    HAVE_TEST_DUMMY2_H = '#define HAVE_TEST_DUMMY2_H 2'
+    zzz_TEST_DUMMY2_H = '#define zzz_TEST_DUMMY2_H 2'
   }
   EOI
 cat config.h >>EOO
@@ -84,8 +84,8 @@ cat config.h >>EOO
   #  define CUSTOM 123
   #endif
 
-  #define HAVE_TEST_DUMMY1_H 1
-  #define HAVE_TEST_DUMMY2_H 2
+  #define zzz_TEST_DUMMY1_H 1
+  #define zzz_TEST_DUMMY2_H 2
   EOO
 
 : basics-cmake
@@ -111,8 +111,8 @@ cat <<EOI >=config.h.in;
   #cmakedefine FALSE false
   #cmakedefine VALUE @VALUE@ /* @version@ */
 
-  #cmakedefine HAVE_TEST_DUMMY1_H @HAVE_TEST_DUMMY1_H@
-  #cmakedefine HAVE_TEST_DUMMY2_H
+  #cmakedefine zzz_TEST_DUMMY1_H @zzz_TEST_DUMMY1_H@
+  #cmakedefine zzz_TEST_DUMMY2_H
   EOI
 $* <<EOI &config.h &config.h.d;
   ./: h{config}: in{config}
@@ -134,7 +134,7 @@ $* <<EOI &config.h &config.h.d;
   #endif
   '
 
-    HAVE_TEST_DUMMY2_H = '#define HAVE_TEST_DUMMY2_H 2'
+    zzz_TEST_DUMMY2_H = '#define zzz_TEST_DUMMY2_H 2'
   }
   EOI
 cat config.h >>EOO
@@ -162,8 +162,8 @@ cat config.h >>EOO
   #undef FALSE
   #define VALUE 123 /* 1.2.3 */
 
-  #define HAVE_TEST_DUMMY1_H 1
-  #define HAVE_TEST_DUMMY2_H 2
+  #define zzz_TEST_DUMMY1_H 1
+  #define zzz_TEST_DUMMY2_H 2
   EOO
 
 : basics-meson
@@ -184,8 +184,8 @@ cat <<EOI >=config.h.in;
   #mesondefine CUSTOM_LINE
   #mesondefine CUSTOM_BLOCK
 
-  #mesondefine HAVE_TEST_DUMMY1_H
-  #mesondefine HAVE_TEST_DUMMY2_H
+  #mesondefine zzz_TEST_DUMMY1_H
+  #mesondefine zzz_TEST_DUMMY2_H
   EOI
 $* <<EOI &config.h &config.h.d;
   ./: h{config}: in{config}
@@ -207,7 +207,7 @@ $* <<EOI &config.h &config.h.d;
   #endif
   '
 
-    HAVE_TEST_DUMMY2_H = '#define HAVE_TEST_DUMMY2_H 2'
+    zzz_TEST_DUMMY2_H = '#define zzz_TEST_DUMMY2_H 2'
   }
   EOI
 cat config.h >>EOO
@@ -227,6 +227,6 @@ cat config.h >>EOO
   #  define CUSTOM 123
   #endif
 
-  #define HAVE_TEST_DUMMY1_H 1
-  #define HAVE_TEST_DUMMY2_H 2
+  #define zzz_TEST_DUMMY1_H 1
+  #define zzz_TEST_DUMMY2_H 2
   EOO

libbuild2-autoconf/libbuild2/autoconf/.gitignore

@@ -1,3 +1,4 @@
-# Generated version header.
+# Generated sources.
 #
-version.hxx
+checks.?xx
+

libbuild2-autoconf/libbuild2/autoconf/buildfile

@@ -4,7 +4,78 @@ impl_libs = # Implementation dependencies.
 import impl_libs += build2%lib{build2} # Implied interface dependency.
 import impl_libs += build2%lib{build2-in}
 
-lib{build2-autoconf}: {hxx ixx txx cxx}{**} $impl_libs $intf_libs
+lib{build2-autoconf}: {hxx ixx txx cxx}{* -checks} {hxx cxx}{checks} \
+                      $impl_libs $intf_libs
+
+# - File name must be the exact variable name plus .h (used for sorting).
+# - First line in the file should be `// <NAME>`.
+# - No double-quote or backslash escaping except for line continuations.
+#
+# NOTE: remember to update README.md if changing anything here.
+#
+<{hxx cxx}{checks}>: checks/file{*.h}
+{
+  install = false
+  backlink = true
+}
+{{
+  diag gen ($>[1])
+
+  # We have to sort without the extension.
+  #
+  i = $regex.apply($sort($base($path($<))), '(.+)', '\1.h')
+
+  h = $path($>[0])
+  s = $path($>[1])
+
+  # We regularize the output with a dummy start entry plus add two end dummies
+  # that are used in tests.
+  #
+  n = $size($<)
+  n += 3
+
+  cat <<"EOI" >$h
+  namespace build2
+  {
+    namespace autoconf
+    {
+      struct check
+      {
+        const char* name;
+        const char* value;
+      };
+
+      extern const check checks[$n];
+    }
+  }
+  EOI
+
+  cat <<"EOI" >$s
+  #include <libbuild2/autoconf/checks.hxx>
+
+  const build2::autoconf::check build2::autoconf::checks[$n] = {
+  {\"\", \"\"
+  EOI
+
+  # @@ TODO: add \n once sed supports it.
+  #
+  cat $i | sed -n \
+    -e 's|^// ([^ ]+) *$|},{"\1",|p' \
+    -e 's|^(.*)\\$|"\1\\\\\\n"|p' \
+    -e 's|^(.*)$|"\1\\n"|p' \
+    - >>$s
+
+  cat <<EOI >>$s
+  },
+  {"zzz_TEST_DUMMY1_H",
+  "#define zzz_TEST_DUMMY1_H 1"
+  },
+  {"zzz_TEST_DUMMY2_H",
+  "#define zzz_TEST_DUMMY2_H 1"
+  }
+  };
+  EOI
+}}
 
 # Build options.
 #

libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_STDLIB_H.h

@@ -0,0 +1,2 @@
+// HAVE_STDLIB_H
+#define HAVE_STDLIB_H 1

libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_STRLCAT.h

@@ -0,0 +1,9 @@
+// HAVE_STRLCAT
+#if defined(__FreeBSD__) || \
+    defined(__OpenBSD__) || \
+    defined(__NetBSD__)  || \
+    defined(__APPLE__)
+#  define HAVE_STRLCAT 1
+#else
+#  undef HAVE_STRLCAT
+#endif

libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_STRLCPY.h

@@ -0,0 +1,9 @@
+// HAVE_STRLCPY
+#if defined(__FreeBSD__) || \
+    defined(__OpenBSD__) || \
+    defined(__NetBSD__)  || \
+    defined(__APPLE__)
+#  define HAVE_STRLCPY 1
+#else
+#  undef HAVE_STRLCPY
+#endif

libbuild2-autoconf/libbuild2/autoconf/checks/STDC_HEADERS.h

@@ -0,0 +1,2 @@
+// STDC_HEADERS
+#define STDC_HEADERS 1

libbuild2-autoconf/libbuild2/autoconf/checks/const.h

@@ -0,0 +1,2 @@
+// const
+#undef const

libbuild2-autoconf/libbuild2/autoconf/checks/inline.h

@@ -0,0 +1,2 @@
+// inline
+#undef inline

libbuild2-autoconf/libbuild2/autoconf/checks/volatile.h

@@ -0,0 +1,2 @@
+// volatile
+#undef volatile

libbuild2-autoconf/libbuild2/autoconf/rule.cxx

@@ -4,6 +4,8 @@
 #include <libbuild2/algorithm.hxx>
 #include <libbuild2/diagnostics.hxx>
 
+#include <libbuild2/autoconf/checks.hxx>
+
 using namespace std;
 
 namespace build2
@@ -364,19 +366,6 @@ namespace build2
       in::rule::process (l, a, t, dd, dd_skip, s, b, nl, sym, strict, null);
     }
 
-    struct check
-    {
-      const char* name;
-      const char* value;
-    };
-
-    // Note: must be sorted.
-    //
-    const check checks[] = {
-      {"HAVE_TEST_DUMMY1_H", "#define HAVE_TEST_DUMMY1_H 1"},
-      {"HAVE_TEST_DUMMY2_H", "#define HAVE_TEST_DUMMY2_H 1"},
-    };
-
     string rule::
     lookup (const location& l,
             action a, const target& t,