diff --git a/Makefile.am b/Makefile.am
index a934a9d..947287d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -58,6 +58,15 @@ CompilerCommands.hs: Makefile
 	echo 'cxxCommand :: String -> String -> String' >> CompilerCommands.hs
 	echo 'cxxCommand inp out = "$(CXX) $(TOCK_CXXFLAGS) -o " ++ out ++ " " ++ inp ++ " $(TOCK_CXXLDFLAGS)"' >> CompilerCommands.hs
 
+TypeSizes.hs: Makefile
+	echo 'module TypeSizes where' > TypeSizes.hs
+	echo '--This file is auto-generated by Makefile.am' >> TypeSizes.hs
+	echo 'cBoolSize, cxxBoolSize, cIntSize, cxxIntSize :: Int' >> TypeSizes.hs
+	echo 'cBoolSize = @C_BOOL_SIZE@' >> TypeSizes.hs
+	echo 'cxxBoolSize = @CXX_BOOL_SIZE@' >> TypeSizes.hs
+	echo 'cIntSize = @C_INT_SIZE@' >> TypeSizes.hs
+	echo 'cxxIntSize = @CXX_INT_SIZE@' >> TypeSizes.hs
+
 # Both these results are near-identical.  The -g flag to alex tells it to generate
 # a lexer optimised for GHC.  The other part of the rule inserts the
 # -fno-warn-tabs flag under GHC >= 6.8, but doesn't add anything under previous
@@ -89,7 +98,7 @@ data/TagAST.hs: GenTagAST$(EXEEXT)
 data/OrdAST.hs: GenOrdAST$(EXEEXT)
 	./GenOrdAST$(EXEEXT) > data/OrdAST.hs
 
-BUILT_SOURCES = frontends/LexOccam.hs frontends/LexRain.hs CompilerCommands.hs data/TagAST.hs data/OrdAST.hs
+BUILT_SOURCES = frontends/LexOccam.hs frontends/LexRain.hs CompilerCommands.hs TypeSizes.hs data/TagAST.hs data/OrdAST.hs
 CLEANFILES = $(BUILT_SOURCES)
 
 EXTRA_DIST = docextra testcases/automatic
diff --git a/configure.ac b/configure.ac
index 2310e23..1fa5323 100644
--- a/configure.ac
+++ b/configure.ac
@@ -140,6 +140,24 @@ fi
 
 AM_CONDITIONAL([GHC68],[test $ghc_version_major -ge 6 -a $ghc_version_mid -ge 8])
 
+# Check the sizes of certain constructs.  We'll need to be cleverer if in future
+# we want to allow cross-compilation.
+AC_LANG(C++)
+AC_CHECK_SIZEOF(bool)
+AC_COMPUTE_INT(CXX_BOOL_SIZE,SIZEOF_BOOL)
+AC_SUBST(CXX_BOOL_SIZE)
+AC_CHECK_SIZEOF(int)
+AC_COMPUTE_INT(CXX_INT_SIZE,SIZEOF_INT)
+AC_SUBST(CXX_INT_SIZE)
+AC_LANG(C)
+AC_CHECK_SIZEOF(_Bool)
+AC_COMPUTE_INT(C_BOOL_SIZE,SIZEOF__BOOL)
+AC_SUBST(C_BOOL_SIZE)
+AC_CHECK_SIZEOF(int)
+AC_COMPUTE_INT(C_INT_SIZE,SIZEOF_INT)
+AC_SUBST(C_INT_SIZE)
+
+
 AC_SUBST(gnu89_inline)
 AC_SUBST(ccsp_kroc_available)
 AC_SUBST(cppcsp_available)