Both make systems now delete src/{pcre2.h,config.h} before starting. The

existence of these files can confuse if building is happening in another 
directory.

CMakeLists.txt

@@ -81,6 +81,7 @@
 # 2017-04-08 PH added HEAP_LIMIT
 # 2017-06-15 ZH added SUPPORT_JIT_SEALLOC support
 # 2018-06-19 PH added checks for stdint.h and inttypes.h
+# 2018-06-21 PH added deletion of src/pcre2.h and src/config.h
 
 PROJECT(PCRE2 C)
 
@@ -130,6 +131,12 @@ CHECK_FUNCTION_EXISTS(bcopy     HAVE_BCOPY)
 CHECK_FUNCTION_EXISTS(memmove   HAVE_MEMMOVE)
 CHECK_FUNCTION_EXISTS(strerror  HAVE_STRERROR)
 
+# Clear out any previously created config.h and pcre2.h in the source 
+# directory so that if we are compiling in a separate build directory there
+# is no confusion.
+
+FILE(REMOVE ${CMAKE_SOURCE_DIR}/src/config.h ${CMAKE_SOURCE_DIR}/src/pcre2.h)
+
 # User-configurable options
 #
 # Note: CMakeSetup displays these in alphabetical order, regardless of

ChangeLog

@@ -85,6 +85,10 @@ standard systems:
   (c) Parameterize the use of %zu in pcre2test to make it like %td. For both of
       these now, if using MSVC or a standard C before C99, %lu is used with a 
       cast if necessary.  
+      
+19. Arrange for "configure" and CMake to delete pcre2.h and config.h from the 
+source directory src so that there is no confusion when building in a different 
+directory if these files happen to be present. 
 
 
 Version 10.31 12-February-2018

configure.ac

@@ -32,6 +32,12 @@ AC_CONFIG_HEADERS(src/config.h)
 # This was added at the suggestion of libtoolize (03-Jan-10)
 AC_CONFIG_MACRO_DIR([m4])
 
+# Clear out any previously created config.h and pcre2.h in the source 
+# directory so that if we are compiling in a separate build directory there
+# is no confusion.
+
+rm -f $srcdir/src/config.h $srcdir/src/pcre2.h
+
 # The default CFLAGS in Autoconf are "-g -O2" for gcc and just "-g" for any
 # other compiler. There doesn't seem to be a standard way of getting rid of the
 # -g (which I don't think is needed for a production library). This fudge seems