If you don't use all the adime_dialogf() formats, then you can declare a list of all formats that you use so that the others don't get linked into the executable. This will only save up to about 10 KB, but see Allegro's documentation (the "Reducing your executable size" section) for more hints on how to get rid of much more size. The list of formats should look like this:
ADIME_BEGIN_FORMAT_LIST
format1
format2
etc...
ADIME_END_FORMAT_LIST
where format1, format2 etc are any of the macros:
ADIME_FORMAT_BOOL ADIME_FORMAT_BUTTON ADIME_FORMAT_STRING ADIME_FORMAT_FILENAME ADIME_FORMAT_VLIST ADIME_FORMAT_LIST ADIME_FORMAT_DATAFILE ADIME_FORMAT_WVLIST ADIME_FORMAT_WLIST ADIME_FORMAT_WDATAFILE ADIME_FORMAT_DIALOGF ADIME_FORMAT_VDIALOGF ADIME_FORMAT_INT ADIME_FORMAT_PINT ADIME_FORMAT_UINT ADIME_FORMAT_PUINT ADIME_FORMAT_SHORT ADIME_FORMAT_PSHORT ADIME_FORMAT_USHORT ADIME_FORMAT_PUSHORT ADIME_FORMAT_CHAR ADIME_FORMAT_PCHAR ADIME_FORMAT_UCHAR ADIME_FORMAT_PUCHAR ADIME_FORMAT_DOUBLE ADIME_FORMAT_PDOUBLE ADIME_FORMAT_FLOAT ADIME_FORMAT_PFLOAT ADIME_FORMAT_LINE ADIME_FORMAT_NOTHING ADIME_FORMAT_BUTTONROW ADIME_FORMAT_CHAINLike in Allegro, this will only work for the statically linked library. Note that ADIME_FORMAT_BUTTONROW and ADIME_FORMAT_CHAIN are used internally, so you shouldn't remove them unless you are sure that you know what you are doing.