looks like we had a long-term confusion for LFLAGS as a set of linker flags and as a set of flex flags. Renamed LFLAGS to FLEXFLAGS for flex input.

dtool/pptempl/Template.gmsvc.pp

@@ -814,7 +814,7 @@ $[TAB] cp $[target_header_prebuilt] $[target_header]
 #if $[HAVE_BISON]
 #define source $[file]
 $[target] : $[file]
-$[TAB] $[FLEX] $[LFLAGS] $[if $[YACC_PREFIX],-P$[YACC_PREFIX]] -olex.yy.c $[file]
+$[TAB] $[FLEX] $[FLEXFLAGS] $[if $[YACC_PREFIX],-P$[YACC_PREFIX]] -olex.yy.c $[file]
 #define source lex.yy.c
 #define script /#include <unistd.h>/d
 $[TAB] $[SED]

dtool/pptempl/Template.nmake.pp

@@ -815,7 +815,7 @@ $[TAB] copy /Y $[osfilename $[target_header_prebuilt]] $[osfilename $[target_hea
 #if $[HAVE_BISON]
 #define source $[file]
 $[osfilename $[target]] : $[osfilename $[file]]
-$[TAB] $[FLEX] $[LFLAGS] $[if $[YACC_PREFIX],-P$[YACC_PREFIX]] -olex.yy.c $[osfilename $[file]]
+$[TAB] $[FLEX] $[FLEXFLAGS] $[if $[YACC_PREFIX],-P$[YACC_PREFIX]] -olex.yy.c $[osfilename $[file]]
 #define source lex.yy.c
 #define script /#include <unistd.h>/d
 $[TAB] $[SED]

dtool/pptempl/Template.unix.pp

@@ -615,7 +615,7 @@ $[TAB] cp $[target_header_prebuilt] $[target_header]
 #if $[HAVE_BISON]
 #define source $[file]
 $[target] : $[file]
-$[TAB] $[FLEX] $[LFLAGS] $[if $[YACC_PREFIX],-P$[YACC_PREFIX]] -olex.yy.c $[file]
+$[TAB] $[FLEX] $[FLEXFLAGS] $[if $[YACC_PREFIX],-P$[YACC_PREFIX]] -olex.yy.c $[file]
 #define source lex.yy.c
 #define script /#include <unistd.h>/d
 $[TAB] $[SED]

panda/src/egg/Sources.pp

@@ -3,6 +3,7 @@
 #define OTHER_LIBS p3interrogatedb:c p3dconfig:c p3dtoolconfig:m \
                    p3dtoolutil:c p3dtoolbase:c p3dtool:m p3prc:c
 #define YACC_PREFIX eggyy
+#define FLEXFLAGS -i
 #define USE_PACKAGES zlib
 
 #begin lib_target

pandatool/src/xfile/Sources.pp

@@ -1,4 +1,5 @@
 #define YACC_PREFIX xyy
+#define FLEXFLAGS -i
 
 #define USE_PACKAGES zlib