eprover: fix cross compilation (#504298)

pkgs/by-name/ep/eprover/fix-cross-toolchains.patch

@@ -0,0 +1,25 @@
+--- a/CONTRIB/picosat-965/makefile.in
++++ b/CONTRIB/picosat-965/makefile.in
+@@ -49,8 +49,7 @@ config.h: makefile VERSION mkconfig.sh # and actually picosat.c
+ 	rm -f $@; ./mkconfig.sh > $@
+ 
+ libpicosat.a: picosat.o version.o
+-	ar rc $@ picosat.o version.o
+-	ranlib $@
++	$(AR) $@ picosat.o version.o
+ 
+ SONAME=-Xlinker -soname -Xlinker libpicosat.so
+ libpicosat.so: picosat.o version.o
+--- a/Makefile.vars
++++ b/Makefile.vars
+@@ -160,8 +160,8 @@ LD         = $(CC) $(LDFLAGS)
+ 
+ # Generic
+ #    AR         = sleep 1;ar rcs
+-   AR         = ar rcs
+-   CC         =  gcc
++#    AR         = ar rcs
++#    CC         =  gcc
+ 
+ # Builds with link time optimization
+ #

pkgs/by-name/ep/eprover/package.nix

@@ -17,9 +17,11 @@ stdenv.mkDerivation (finalAttrs: {
 
   buildInputs = [ which ];
 
-  preConfigure = ''
-    sed -e 's/ *CC *= *gcc$//' -i Makefile.vars
-  '';
+  patches = [
+    ./fix-cross-toolchains.patch
+  ];
+
+  configurePlatforms = [ ];
 
   configureFlags = [
     "--exec-prefix=$(out)"
@@ -29,6 +31,14 @@ stdenv.mkDerivation (finalAttrs: {
     "--enable-ho"
   ];
 
+  # need to directly insert into makeFlagsArray as the makefile expects the binary
+  # in the AR variable to already be passed the `rcs` flags, which requires us to
+  # specify them. As this requires spaces, we need makeFlagsArray, as makeFlags
+  # will just make the make script see the `rcs` as a target
+  preBuild = ''
+    makeFlagsArray+=(CC="${stdenv.cc.targetPrefix}cc" AR="${stdenv.cc.targetPrefix}ar rcs")
+  '';
+
   meta = {
     description = "Automated theorem prover for full first-order logic with equality";
     homepage = "http://www.eprover.org/";