--- wikisrc/pkgsrc/gcc.mdwn	2017/11/26 01:20:23	1.2
+++ wikisrc/pkgsrc/gcc.mdwn	2017/11/26 01:28:44	1.3
@@ -18,7 +18,7 @@ build gcc versions (typically newer vers
 in a compiler within ${PREFIX}, e.g. /usr/pkg/gcc6/bin/gcc.  This
 compiler can then be used to compile other packages.
 
-Issues with using base system gcc are typically that it is too old,
+The Issue with using base system gcc is typically that it is too old,
 such as gcc 4.5 with NetBSD 6, which cannot compile c++11.
 
 Issues when using pkgsrc gcc are that
@@ -47,9 +47,9 @@ This section attempts to gather all the 
     version used in any included library.
 
   - All packages that use C++ should be built with the same compiler
-    version.  Because these typically also include C, the version used
-    for C++ must be at least as new as the version used for any used C
-    package.
+    version.  Because these in the general case may include C, the
+    version used for C++ must be at least as new as the version used
+    for any used C package.
 
   - pkgsrc should avoid building gcc unless it is more or less
     necessary to build packges.  (As an example, if the base system
@@ -102,8 +102,8 @@ sound while mimimizing complexity.
     package building will fail.  We call the resulting
     PKGSRC_GCC_VERSION or PKGSRC_GXX_VERSION the chosen version.
 
-  - When building a program using C or C++, the chosen version is not
-    provided by the base system, and the chosen version is not
+  - When building a program using C or C++, if the chosen version is
+    not provided by the base system, and the chosen version is not
     installed via pkgsrc, then it (and its dependencies) will be built
     from pkgsrc in a special bootstrap mode.  When building in
     bootstrap mode, the version selection logic is ignored and the
@@ -151,19 +151,28 @@ exist.
 \todo: Discuss adjusting options to minimize dependencies, including
 gcc-inplace-math and nls.
 
+### Differing GCC and GXX versions
+
+Perhaps it is a mistake to allow the chosen GCC and GXX versions to
+differ.  If we require them to be the same, then essentially all
+systems with a base system compiler older than gcc 5 will have to
+bootstrap the compiler.  For now, we allow them to differ and will
+permit the defaults to differ.
+
 ### Default versions for various systems
 
-Note that if any particular system (or bulk build), a newer gcc has to
-be built, it does not hurt incrementally to have built it earlier.
+Note that if for any particular system's set of installed packages (or
+bulk build), a newer gcc has to be built, it does not hurt to have
+built it earlier.
 
 When the base system is old (e.g., gcc 4.5 in NetBSD 6, or 4.1, in
 NetBSD 5), then it is clear that a newer version must be built.  For
 these, PKGSRC_GXX_VERSION should default to a newish gcc, avoiding
 being so new as to cause building issues.  Currently, gcc6 is probably
 a good choice.  PKGSRC_GCC_VERSION should probably default to the
-system version if it can build C99, or match PKGSRC_GXX_VERSION, if
-the system version is too old.  Perhaps gcc 4.5 would be used, but 4.1
-not used.  \todo Discuss.
+system version if it can build all C99 programs, or match
+PKGSRC_GXX_VERSION, if the system version is too old.  Perhaps gcc 4.5
+would be used, but 4.1 not used.  \todo Discuss.
 
 When the base system is almost new enough, the decision about the
 default is more complicated.  A key example is gcc 4.8, found in
@@ -219,3 +228,7 @@ not worsened by the above design.  \todo
    is the base system version if >= 4.5 (or 4.4?), and otherwise 6,
    and that PKGSRC_GXX_VERSION is the base system version if >= 5, and
    otherwise 6.
+
+### Later steps
+
+ - Address fortran.