Check members only for defined structs

Author: nobu

ext/etc/extconf.rb

@@ -10,8 +10,30 @@
 have_library("sun", "getpwnam")	# NIS (== YP) interface for IRIX 4
 have_func("uname((struct utsname *)NULL)", headers)
 have_func("getlogin")
-have_func("getpwent")
-have_func("getgrent")
+if have_func("getpwent")
+  have_struct_member('struct passwd', 'pw_gecos', 'pwd.h')
+  have_struct_member('struct passwd', 'pw_change', 'pwd.h')
+  have_struct_member('struct passwd', 'pw_quota', 'pwd.h')
+  if have_struct_member('struct passwd', 'pw_age', 'pwd.h')
+    case what_type?('struct passwd', 'pw_age', 'pwd.h')
+    when "string"
+      f = "safe_setup_str"
+    when "long long"
+      f = "LL2NUM"
+    else
+      f = "INT2NUM"
+    end
+    $defs.push("-DPW_AGE2VAL="+f)
+  end
+  have_struct_member('struct passwd', 'pw_class', 'pwd.h')
+  have_struct_member('struct passwd', 'pw_comment', 'pwd.h') unless /cygwin/ === RUBY_PLATFORM
+  have_struct_member('struct passwd', 'pw_expire', 'pwd.h')
+  have_struct_member('struct passwd', 'pw_passwd', 'pwd.h')
+end
+if have_func("getgrent")
+  have_struct_member('struct group', 'gr_passwd', 'grp.h')
+end
+
 if (sysconfdir = RbConfig::CONFIG["sysconfdir"] and
     !RbConfig.expand(sysconfdir.dup, "prefix"=>"", "DESTDIR"=>"").empty?)
   $defs.push("-DSYSCONFDIR=#{Shellwords.escape(sysconfdir.dump)}")
@@ -21,26 +43,6 @@
 have_func("confstr")
 have_func("fpathconf")
 
-have_struct_member('struct passwd', 'pw_gecos', 'pwd.h')
-have_struct_member('struct passwd', 'pw_change', 'pwd.h')
-have_struct_member('struct passwd', 'pw_quota', 'pwd.h')
-if have_struct_member('struct passwd', 'pw_age', 'pwd.h')
-  case what_type?('struct passwd', 'pw_age', 'pwd.h')
-  when "string"
-    f = "safe_setup_str"
-  when "long long"
-    f = "LL2NUM"
-  else
-    f = "INT2NUM"
-  end
-  $defs.push("-DPW_AGE2VAL="+f)
-end
-have_struct_member('struct passwd', 'pw_class', 'pwd.h')
-have_struct_member('struct passwd', 'pw_comment', 'pwd.h') unless /cygwin/ === RUBY_PLATFORM
-have_struct_member('struct passwd', 'pw_expire', 'pwd.h')
-have_struct_member('struct passwd', 'pw_passwd', 'pwd.h')
-have_struct_member('struct group', 'gr_passwd', 'grp.h')
-
 # for https://github.com/ruby/etc
 srcdir = File.expand_path("..", __FILE__)
 constdefs = "#{srcdir}/constdefs.h"