15 files changed, 50 insertions, 0 deletions
diff --git a/Configure b/Configure
index 44920204aa..84a34bf597 100755
--- a/Configure
+++ b/Configure
@@ -937,6 +937,7 @@ d_wcstombs=''
 d_wcsxfrm=''
 d_wctomb=''
 d_writev=''
+default_inc_excludes_dot=''
 dlext=''
 bin_ELF=''
 cccdlflags=''
@@ -20625,6 +20626,28 @@ EOCP
 	;;
 esac
 
+: Include . in @INC
+$cat <<EOM
+
+Historically Perl has provided a final fallback of the current working
+directory '.' when searching for a library. This, however, can lead to
+problems when a Perl program which loads optional modules is called from
+a shared directory. This can lead to executing unexpected code.
+
+EOM
+
+case "$default_inc_excludes_dot" in
+    $define|true|[yY]*) dflt="n" ;;
+    *)                  dflt='y' ;;
+esac
+
+rp='Provide '.' in @INC by default? '
+. ./myread
+case "$ans" in
+    [nN]*|define) default_inc_excludes_dot="$define" ;;
+    *)            default_inc_excludes_dot="$undef"  ;;
+esac
+
 : Check what kind of inf/nan your system has
 $echo "Checking the kind of infinities and nans you have..." >&4
 $echo "(The following tests may crash.  That's okay.)" >&4
@@ -24913,6 +24936,7 @@ db_prefixtype='$db_prefixtype'
 db_version_major='$db_version_major'
 db_version_minor='$db_version_minor'
 db_version_patch='$db_version_patch'
+default_inc_excludes_dot='$default_inc_excludes_dot'
 direntrytype='$direntrytype'
 dlext='$dlext'
 dlsrc='$dlsrc'
diff --git a/Cross/config.sh-arm-linux b/Cross/config.sh-arm-linux
index 2626400cdb..a20d723879 100644
--- a/Cross/config.sh-arm-linux
+++ b/Cross/config.sh-arm-linux
@@ -637,6 +637,7 @@ db_prefixtype='size_t'
 db_version_major=''
 db_version_minor=''
 db_version_patch=''
+default_inc_excludes_dot=''
 direntrytype='struct dirent'
 dlext='so'
 dlsrc='dl_dlopen.xs'
diff --git a/NetWare/config.wc b/NetWare/config.wc
index 176a86592e..8535885611 100644
--- a/NetWare/config.wc
+++ b/NetWare/config.wc
@@ -628,6 +628,7 @@ db_version_minor='0'
 db_version_patch='0'
 def_perlroot='sys:\perl\scripts'
 def_temp='sys:\perl\temp'
+default_inc_excludes_dot=''
 direntrytype='DIR'
 dlext='nlm'
 dlsrc='dl_netware.xs'
diff --git a/Porting/Glossary b/Porting/Glossary
index 522d3562ef..1d2a6ea988 100644
--- a/Porting/Glossary
+++ b/Porting/Glossary
@@ -2959,6 +2959,9 @@ db_version_patch (i_db.U):
 	Berkeley DB found in the <db.h> header file.
 	For DB version 1 this is always 0.
 
+default_inc_excludes_dot (defaultincdot.U):
+	When defined, remove the legacy '.' from @INC
+
 direntrytype (i_dirent.U):
 	This symbol is set to 'struct direct' or 'struct dirent' depending on
 	whether dirent is available or not. You should use this pseudo type to
diff --git a/Porting/config.sh b/Porting/config.sh
index ff6a5fe3ee..c9aa2c2f1f 100644
--- a/Porting/config.sh
+++ b/Porting/config.sh
@@ -650,6 +650,7 @@ db_prefixtype='int'
 db_version_major='1'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct dirent'
 dlext='bundle'
 dlsrc='dl_dlopen.xs'
diff --git a/config_h.SH b/config_h.SH
index c722657e2e..e9b144f02b 100755
--- a/config_h.SH
+++ b/config_h.SH
@@ -3736,6 +3736,12 @@ sed <<!GROK!THIS! >$CONFIG_H -e 's!^#undef\(.*/\)\*!/\*#define\1 \*!' -e 's!^#un
  */
 #$d_writev HAS_WRITEV		/**/
 
+/* DEFAULT_INC_EXCLUDES_DOT:
+ *	This symbol, if defined, removes the legacy default behavior of
+ *	including '.' at the end of @INC.
+ */
+#$default_inc_excludes_dot DEFAULT_INC_EXCLUDES_DOT	/**/
+
 /* USE_DYNAMIC_LOADING:
  *	This symbol, if defined, indicates that dynamic loading of
  *	some sort is available.
diff --git a/configure.com b/configure.com
index 888d2d08f9..090d2efc8b 100644
--- a/configure.com
+++ b/configure.com
@@ -6452,6 +6452,7 @@ $ WC "db_version_minor='" + "'"
 $ WC "db_version_patch='" + "'"
 $ WC "dbgprefix='" + dbgprefix + "'"
 $ WC "devtype='" + devtype + "'"
+$ WC "default_inc_excludes_dot=''"
 $ WC "direntrytype='struct dirent'"
 $ WC "dlext='" + dlext + "'"
 $ WC "dlobj='" + dlobj + "'"
diff --git a/plan9/config_sh.sample b/plan9/config_sh.sample
index 9851e22de4..e7078a0313 100644
--- a/plan9/config_sh.sample
+++ b/plan9/config_sh.sample
@@ -636,6 +636,7 @@ db_prefixtype='size_t'
 db_version_major=''
 db_version_minor=''
 db_version_patch=''
+default_inc_excludes_dot=''
 direntrytype='struct dirent'
 dlext='none'
 dlsrc='dl_none.xs'
diff --git a/symbian/config.sh b/symbian/config.sh
index 1c08bd3989..e6ca7fb2c6 100644
--- a/symbian/config.sh
+++ b/symbian/config.sh
@@ -583,6 +583,7 @@ db_prefixtype='size_t'
 db_version_major='0'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct dirent'
 dlext='dll'
 dlsrc='dl_symbian.xs'
diff --git a/uconfig.h b/uconfig.h
index d2c6a48892..1540513e2d 100644
--- a/uconfig.h
+++ b/uconfig.h
@@ -3701,6 +3701,12 @@
  */
 /*#define HAS_WRITEV		/ **/
 
+/* DEFAULT_INC_EXCLUDES_DOT:
+ *	This symbol, if defined, removes the legacy default behavior of
+ *	including '.' at the end of @INC.
+ */
+# DEFAULT_INC_EXCLUDES_DOT	/**/
+
 /* USE_DYNAMIC_LOADING:
  *	This symbol, if defined, indicates that dynamic loading of
  *	some sort is available.
diff --git a/uconfig.sh b/uconfig.sh
index 3174bba1eb..a7b2615b2f 100644
--- a/uconfig.sh
+++ b/uconfig.sh
@@ -574,6 +574,7 @@ db_prefixtype='size_t'
 db_version_major='0'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct dirent'
 doubleinfbytes='0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x7f'
 doublekind='3'
diff --git a/uconfig64.sh b/uconfig64.sh
index 1eb7eac170..27d4a180a8 100644
--- a/uconfig64.sh
+++ b/uconfig64.sh
@@ -575,6 +575,7 @@ db_prefixtype='size_t'
 db_version_major='0'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct dirent'
 doubleinfbytes='0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x7f'
 doublekind='3'
diff --git a/win32/config.ce b/win32/config.ce
index 47042d88c2..3005086aef 100644
--- a/win32/config.ce
+++ b/win32/config.ce
@@ -624,6 +624,7 @@ db_prefixtype='int'
 db_version_major='0'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct direct'
 dlext='dll'
 dlsrc='dl_win32.xs'
diff --git a/win32/config.gc b/win32/config.gc
index 34b670e000..b726e7d3d9 100644
--- a/win32/config.gc
+++ b/win32/config.gc
@@ -625,6 +625,7 @@ db_prefixtype='int'
 db_version_major='0'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct direct'
 dlext='dll'
 dlltool='~ARCHPREFIX~dlltool'
diff --git a/win32/config.vc b/win32/config.vc
index cfac6e7ca2..5731b88dde 100644
--- a/win32/config.vc
+++ b/win32/config.vc
@@ -625,6 +625,7 @@ db_prefixtype='int'
 db_version_major='0'
 db_version_minor='0'
 db_version_patch='0'
+default_inc_excludes_dot=''
 direntrytype='struct direct'
 dlext='dll'
 dlsrc='dl_win32.xs'