4 files changed, 39 insertions, 34 deletions
diff --git a/etc/environments/default b/etc/environments/default
index f4a19aa..92bc5fd 100755
--- a/etc/environments/default
+++ b/etc/environments/default
@@ -4,7 +4,13 @@
 # copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
 # license   : TBC; see accompanying LICENSE file
 
+#
 # Environment setup script for C/C++ compilation.
+#
+# Note that we assume the compiler's default target is x86_64-* and, if
+# requested, i?86-* can be selected with -m32. For other targets you will
+# need to adjust the mode selection below.
+#
 
 c=gcc
 cxx=g++
@@ -15,12 +21,20 @@ cxx=g++
 
 set -e # Exit on errors.
 
-t="$1"
+# Based on target determine what we are building.
+#
+case "$1" in
+  x86_64-*)
+    mode=
+    ;;
+  i?86-*)
+    mode="config.cc.coptions+=-m32"
+    ;;
+  *)
+    echo "unknown target: '$1'" 1>&2
+    exit 1
+    ;;
+esac
 shift
 
-if test -n "$t"; then
-  echo "unknown target: $t" 1>&2
-  exit 1
-fi
-
-exec "$@" cc config.c="$c" config.cxx="$cxx"
+exec "$@" cc config.c="$c" config.cxx="$cxx" $mode
diff --git a/etc/environments/default-mingw.bat b/etc/environments/default-mingw.bat
index 3d9bcb1..0491882 100644
--- a/etc/environments/default-mingw.bat
+++ b/etc/environments/default-mingw.bat
@@ -7,6 +7,9 @@ rem license   : TBC; see accompanying LICENSE file
 rem
 rem Environment setup script for C/C++ compilation with MinGW GCC.
 rem
+rem Note that we assume the compiler's default target is x86_64-w64-mingw32
+rem and, if requested, i686-w64-mingw32 can be selected with -m32.
+rem
 
 rem %1  - target
 rem %2  - bbot executable
@@ -20,16 +23,18 @@ set "PATH=$MINGW;%PATH%"
 
 rem Based on target determine what we are building.
 rem
-rem Note that an empty argument is passed as "" (literal quotes).
-rem
-if _%1_ == _""_ (
-  rem
+if "_%1_" == "_x86_64-w64-mingw32_" (
+  set "mode="
 ) else (
-  echo error: unknown target %1
-  goto error
+  if "_%1_" == "_i686-w64-mingw32_" (
+    set "mode=config.cc.coptions+=-m32"
+  ) else (
+    echo error: unknown target %1
+    goto error
+  )
 )
 
-%2 %3 %4 %5 %6 %7 %8 %9 cc config.c=gcc config.cxx=g++
+%2 %3 %4 %5 %6 %7 %8 %9 cc config.c=gcc config.cxx=g++ %mode%
 if errorlevel 1 goto error
 
 goto end
diff --git a/etc/environments/default-msvc-14.bat b/etc/environments/default-msvc-14.bat
index 2af8136..fe8ebb4 100644
--- a/etc/environments/default-msvc-14.bat
+++ b/etc/environments/default-msvc-14.bat
@@ -17,10 +17,7 @@ setlocal EnableExtensions EnableDelayedExpansion
 set "MSVC=C:\Program Files (x86)\Microsoft Visual Studio 14.0"
 set "VCVARS=%MSVC%\VC\vcvarsall.bat"
 
-rem Based on target determine what we are building. If the target is
-rem not specified, then we build 64-bit by default.
-rem
-rem Note that an empty argument is passed as "" (literal quotes).
+rem Based on target determine what we are building.
 rem
 if "_%1_" == "_x86_64-microsoft-win32-msvc14.0_" (
   set "VCARCH=amd64"
@@ -28,12 +25,8 @@ if "_%1_" == "_x86_64-microsoft-win32-msvc14.0_" (
   if "_%1_" == "_i386-microsoft-win32-msvc14.0_" (
     set "VCARCH=amd64_x86"
   ) else (
-    if _%1_ == _""_ (
-      set "VCARCH=amd64"
-    ) else (
-      echo error: unknown target %1
-      goto error
-    )
+    echo error: unknown target %1
+    goto error
   )
 )
 
diff --git a/etc/environments/default-msvc-15.bat b/etc/environments/default-msvc-15.bat
index 6eecc71..6c900dd 100644
--- a/etc/environments/default-msvc-15.bat
+++ b/etc/environments/default-msvc-15.bat
@@ -19,10 +19,7 @@ set "MSVC=C:\Program Files (x86)\Microsoft Visual Studio\2017\Community"
 set "VCVARS32=%MSVC%\VC\Auxiliary\Build\vcvarsamd64_x86.bat"
 set "VCVARS64=%MSVC%\VC\Auxiliary\Build\vcvars64.bat"
 
-rem Based on target determine what we are building. If the target is
-rem not specified, then we build 64-bit by default.
-rem
-rem Note that an empty argument is passed as "" (literal quotes).
+rem Based on target determine what we are building.
 rem
 if "_%1_" == "_x86_64-microsoft-win32-msvc14.1_" (
   set "VCVARS=%VCVARS64%"
@@ -30,12 +27,8 @@ if "_%1_" == "_x86_64-microsoft-win32-msvc14.1_" (
   if "_%1_" == "_i386-microsoft-win32-msvc14.1_" (
     set "VCVARS=%VCVARS32%"
   ) else (
-    if _%1_ == _""_ (
-      set "VCVARS=%VCVARS64%"
-    ) else (
-      echo error: unknown target %1
-      goto error
-    )
+    echo error: unknown target %1
+    goto error
   )
 )