Improve fixes to 1990/dds

Two things had to be done here to make the code look much more like the
original (though it is hardly discernible at first glance).

First thing was I redefined free() to be free() + the comma operator as
it was a binary expression error in modern systems (this fix was
provided by Yusuke Endoh).

The second one was an improvement to one of my earlier several fixes and
in particular the prevention of warnings that cannot be disabled at
compilation/linking/runtime (the latter of which can be interspersed
with the output of the program): gets() to fgets(). The way this was
done is redefining gets() to use fgets(). The second and third arg are
the same so it was possible to just redefine gets() to use fgets() but
gets() having one arg like the original function. It should be noticed
that the original code used fgets() in one case because it has to read
from a different FILE * than stdin so there still is a reference to
fgets() that is not part of the macros.

1990/dds/dds.c

@@ -6,13 +6,14 @@
 #define X ;break;case
 #define _ return
 #define R 999
+#define gets(x) fgets((x),R,stdin)
 typedef char*A;int*C,E[R],L[R],M[R],P[R],l,i,j;char B[R],F[2];A m[12*R],malloc
 (),p,q,x,y,z,s,d;FILE *f;A Q(s,o)A s,o;{for(x=s;*x;x++){for(y=x,z=o;*z&&*y==
-*z;y++)z++;if(z>o&&!*z)_ x;}_	0;}main(){m[11*R]="E";while(puts("Ok"),fgets(B,R,stdin),
+*z;y++)z++;if(z>o&&!*z)_ x;}_	0;}main(){m[11*R]="E";while(puts("Ok"),gets(B),
 B[strlen(B)-1]='\0',1)switch(*B){X'R':C=E;l=1;for(i=0;i<R;P[i++]=0);while(l){while(!(s=m[l]))l++;if
 (!Q(s,"\"")){U("<>",'#');U("<=",'$');U(">=",'!');}d=B;while(*F=*s){*s=='"'&&j
 ++;if(j&1||!Q(" \t",F))*d++=*s;s++;}*d--=j=0;if(B[1]!='=')switch(*B){X'E':l=-1
-X'R':B[2]!='M'&&(l=*--C)X'I':B[1]=='N'?fgets(p=B,R,stdin),P[*d]=S():(*(q=Q(B,"TH"))=0,p
+X'R':B[2]!='M'&&(l=*--C)X'I':B[1]=='N'?gets(p=B),P[*d]=S():(*(q=Q(B,"TH"))=0,p
 =B+2,S()&&(p=q+4,l=S()-1))X'P':B[5]=='"'?*d=0,puts(B+6):(p=B+5,printf("%d\n",S
 ()))X'G':p=B+4,B[2]=='S'&&(*C++=l,p++),l=S()-1 X'F':*(q=Q(B,"TO"))=0;p=B+5;P[i
 =B[3]]=S();p=q+2;M[i]=S();L[i]=l X'N':++P[*d]<=M[*d]&&(l=L[*d]);}else p=B+2,P[