diff --git a/var/spack/repos/builtin/packages/fastx-toolkit/package.py b/var/spack/repos/builtin/packages/fastx-toolkit/package.py
index c1e74163d0..789006ea8b 100644
--- a/var/spack/repos/builtin/packages/fastx-toolkit/package.py
+++ b/var/spack/repos/builtin/packages/fastx-toolkit/package.py
@@ -17,4 +17,5 @@ class FastxToolkit(AutotoolsPackage):
 
     depends_on('libgtextutils')
 
-    conflicts('%gcc@7.1.0:')
+    # patch implicit fallthrough
+    patch("pr-22.patch")
diff --git a/var/spack/repos/builtin/packages/fastx-toolkit/pr-22.patch b/var/spack/repos/builtin/packages/fastx-toolkit/pr-22.patch
new file mode 100644
index 0000000000..75111f6986
--- /dev/null
+++ b/var/spack/repos/builtin/packages/fastx-toolkit/pr-22.patch
@@ -0,0 +1,11 @@
+diff -ur fastx_toolkit-0.0.14.orig/src/fasta_formatter/fasta_formatter.cpp fastx_toolkit-0.0.14/src/fasta_formatter/fasta_formatter.cpp
+--- fastx_toolkit-0.0.14.orig/src/fasta_formatter/fasta_formatter.cpp	2014-01-05 13:10:49.000000000 -0800
++++ fastx_toolkit-0.0.14/src/fasta_formatter/fasta_formatter.cpp	2018-12-31 09:58:21.923778569 -0800
+@@ -103,6 +103,7 @@
+ 		switch(opt) {
+ 		case 'h':
+ 			usage();
++			break;
+ 		
+ 		case 'i':
+ 			input_filename = optarg;