docs/known-issues: add the infamous "mixed implicit and normal rules"

make-3.82 now refuses to have both normal and implicit rules in the
same definition, so document the issue with a known workaround.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

docs/B - Known issues.txt

@@ -197,17 +197,39 @@ Symptoms:
   glibc start files and headers fail with: [/usr/include/limits.h] Error 1
 
 Explanations:
-  The glibc Makefiles break with make-3.82.
+  Old glibc (and eglibc) Makefiles break with make-3.82.
 
 Status:
   CURRENT
 
 Fix:
-  None so far. It would require some glibc hacking.
+  None so far. It would require some glibc/eglibc hacking.
 
 Workaround:
   There two possible workarounds:
-  1- ask crosstool-NG to build make-3.81 just for this build session;
+  1- ask crosstool-NG to build make-3.81 just for this build session:
+     Select the following options:
+        Paths and misc options  --->
+            [*] Try features marked as EXPERIMENTAL
+        Companion tools  --->
+            [*] Build some companion tools
+            [*]   make
   2- manually install make-3.81 to take precedence over the system make.
 
 --------------------------------
+Symptoms:
+  The build fails with "mixed implicit and normal rules. Stop."
+
+Explanations:
+  Old glibc (and eglibc) Makefiles break with make-3.82.
+
+Status:
+  CURRENT
+
+Fix:
+  None so far. See above issue.
+
+Workaround:
+  See above issue.
+
+--------------------------------