Fix warning: redefinition of typedef 'MPLndsets' [-Wpedantic]

[ms609]

Warning generated in https://www.r-project.org/nosvn/R.check/r-devel-windows-ix86+x86_64/TreeSearch-00install.html

morphydefs.h:103:3: warning: redefinition of typedef 'MPLcharinfo' [-Wpedantic]
 } MPLcharinfo;
   ^
morphydefs.h:83:27: note: previous declaration of 'MPLcharinfo' was here
 typedef struct charinfo_s MPLcharinfo;
                           ^
morphydefs.h:113:28: warning: redefinition of typedef 'MPLpartition' [-Wpedantic]
 typedef struct partition_s MPLpartition;
                            ^
morphydefs.h:48:28: note: previous declaration of 'MPLpartition' was here
 typedef struct partition_s MPLpartition;
                            ^
morphydefs.h:148:3: warning: redefinition of typedef 'MPLpartition' [-Wpedantic]
 } MPLpartition;
   ^
morphydefs.h:113:28: note: previous declaration of 'MPLpartition' was here
 typedef struct partition_s MPLpartition;
                            ^
morphydefs.h:172:3: warning: redefinition of typedef 'MPLndsets' [-Wpedantic]
 } MPLndsets;
   ^

(I've not tested whether this fixes the error, or indeed whether it works...)