Added a clarification commentary on the petsc-build package.

mingw-w64-petsc/PKGBUILD

@@ -3,10 +3,13 @@
 _realname=petsc
 pkgbase=mingw-w64-${_realname}
 pkgname=("${MINGW_PACKAGE_PREFIX}-${_realname}" "${MINGW_PACKAGE_PREFIX}-${_realname}-build")
+# The `petsc-build` package contains the distilled PETSc build tree
+# required at compile time by some packages (such as SLEPc).
+# Regular users should use the `petsc` package.
 pkgver=3.14.1
 pkgrel=1
 arch=('any')
-pkgdesc="Sparse iterative (non)linear solver package (mingw-w64)"
+pkgdesc='Sparse iterative (non)linear solver package (mingw-w64)'
 depends=("${MINGW_PACKAGE_PREFIX}-gcc-libs"
          "${MINGW_PACKAGE_PREFIX}-gcc-libgfortran"	
          "${MINGW_PACKAGE_PREFIX}-openblas"
@@ -14,14 +17,14 @@ depends=("${MINGW_PACKAGE_PREFIX}-gcc-libs"
          "${MINGW_PACKAGE_PREFIX}-metis"
          "${MINGW_PACKAGE_PREFIX}-scotch"
          "${MINGW_PACKAGE_PREFIX}-msmpi")
-makedepends=("python"
+makedepends=('python'
              "${MINGW_PACKAGE_PREFIX}-gcc"
              "${MINGW_PACKAGE_PREFIX}-gcc-fortran")
 options=('strip' 'staticlibs')
 license=('2-clause BSD')
 url="https://www.mcs.anl.gov/petsc/"
 source=("http://ftp.mcs.anl.gov/pub/petsc/release-snapshots/${_realname}-lite-${pkgver}.tar.gz"
-        "0001-mpi-detection-override.patch")
+        '0001-mpi-detection-override.patch')
 noextract=("${_realname}-lite-${pkgver}.tar.gz")
 sha256sums=('0b4681165a9af96594c794b97ac6993452ec902726679f6b50bb450f89d230ed'
             'a28912b086807df7381abaec28353023a148f17a594abb6a1478f3b7b434373b')
@@ -35,12 +38,13 @@ prepare() {
   done
 }
 
-builds="dso dto dmo zso zto zmo sso sto smo cso cto cmo"
+builds='dso dto dmo zso zto zmo sso sto smo cso cto cmo'
 
 _petsc() {
   opts="--with-single-library=0 --disable-shared --with-windows-graphics=0 --with-x=0 --with-openblas=1 --with-openblas-dir=$MINGW_PREFIX"
   ld=gfortran
   pc=openblas
+  xflags=-msse # SSE support is required for proper FP trapping
   iflags=
   ldflags=
   desc=
@@ -83,21 +87,20 @@ _petsc() {
       desc="$desc complex"
     ;;
   esac
-  cf=-msse # SSE support is required for FP trapping
   case $1 in
     *o)
       opts="$opts --with-debugging=0"
-      cflags="$CFLAGS $cf"
-      cxxflags="$CXXFLAGS $cf"
-      fflags="$CFLAGS $cf"
+      cflags="$CFLAGS $xflags"
+      cxxflags="$CXXFLAGS $xflags"
+      fflags="$CFLAGS $xflags"
       options=('strip' 'staticlibs')
     ;;
     *g)
       opts="$opts --with-debugging=1"
       debug="-g -Og"
-      cflags="$CFLAGS $debug $cf"
-      cxxflags="$CXXFLAGS $debug $cf"
-      fflags="$CFLAGS $debug $cf"
+      cflags="$CFLAGS $debug $xflags"
+      cxxflags="$CXXFLAGS $debug $xflags"
+      fflags="$CFLAGS $debug $xflags"
       options=('!strip' 'staticlibs')
     ;;
   esac
@@ -185,7 +188,7 @@ _package_build() {
       ${_realname}-${pkgver}/${build}/lib/petsc/conf/petscvariables
   done
   echo "
-    petsc_ver=${pkgver}
+    petsc_pkgver=${pkgver}
     petsc_builds=\"${builds}\"
   " | sed '/^\s*$/d;s/^\s*//' > ${_realname}-${pkgver}/petsc
 }