diff -uNr gnupg-2.2.8/g10/exec.c gnupg-2.2.8.mod/g10/exec.c
--- gnupg-2.2.8/g10/exec.c	2017-08-28 13:22:54.000000000 +0300
+++ gnupg-2.2.8.mod/g10/exec.c	2018-06-19 19:08:38.918070875 +0300
@@ -383,7 +383,7 @@
 	  char *shell=getenv("SHELL");
 
 	  if(shell==NULL)
-	    shell="/bin/sh";
+	    shell="@TERMUX_PREFIX@/bin/sh";
 
 	  /* I'm the child */